tests: replace pycodestyle with black

Drop pycodestyle for code style checking in favor of black. Black is
much faster, stable PEP8 compliant code style checker offering also
automatic formatting. It aims to be very stable and produce smallest
diffs. It's used by many small and big projects.

Running checkstyle with black takes a few seconds with a terse output.
Thus, test-checkstyle-diff is no longer necessary.

Expand scope of checkstyle to all python files in the repo, replacing
test-checkstyle with checkstyle-python.

Also, fixstyle-python is now available for automatic style formatting.

Note: python virtualenv has been consolidated in test/Makefile,
test/requirements*.txt which will eventually be moved to a central
location.  This is required to simply the automated generation of
docker executor images in the CI.

Type: improvement
Change-Id: I022a326603485f58585e879ac0f697fceefbc9c8
Signed-off-by: Klement Sekera <klement.sekera@gmail.com>
Signed-off-by: Dave Wallace <dwallacelf@gmail.com>

1 files changed, 1201 insertions, 873 deletions

diff --git a/test/test_bfd.py b/test/test_bfd.py
index d1c7b92d89d..c7ea79abfd0 100644
--- a/test/test_bfd.py
+++ b/test/test_bfd.py
@@ -21,8 +21,15 @@ from scapy.layers.l2 import Ether, GRE
 from scapy.packet import Raw
 
 from config import config
-from bfd import VppBFDAuthKey, BFD, BFDAuthType, VppBFDUDPSession, \
-    BFDDiagCode, BFDState, BFD_vpp_echo
+from bfd import (
+    VppBFDAuthKey,
+    BFD,
+    BFDAuthType,
+    VppBFDUDPSession,
+    BFDDiagCode,
+    BFDState,
+    BFD_vpp_echo,
+)
 from framework import tag_fixme_vpp_workers
 from framework import VppTestCase, VppTestRunner
 from framework import tag_run_solo
@@ -30,8 +37,7 @@ from util import ppp
 from vpp_ip import DpoProto
 from vpp_ip_route import VppIpRoute, VppRoutePath
 from vpp_lo_interface import VppLoInterface
-from vpp_papi_provider import UnexpectedApiReturnValueError, \
-    CliFailedCommandError
+from vpp_papi_provider import UnexpectedApiReturnValueError, CliFailedCommandError
 from vpp_pg_interface import CaptureTimeoutError, is_ipv6_misc
 from vpp_gre_interface import VppGreInterface
 from vpp_papi import VppEnum
@@ -46,15 +52,17 @@ class AuthKeyFactory(object):
         self._conf_key_ids = {}
 
     def create_random_key(self, test, auth_type=BFDAuthType.keyed_sha1):
-        """ create a random key with unique conf key id """
+        """create a random key with unique conf key id"""
         conf_key_id = randint(0, 0xFFFFFFFF)
         while conf_key_id in self._conf_key_ids:
             conf_key_id = randint(0, 0xFFFFFFFF)
         self._conf_key_ids[conf_key_id] = 1
         key = scapy.compat.raw(
-            bytearray([randint(0, 255) for _ in range(randint(1, 20))]))
-        return VppBFDAuthKey(test=test, auth_type=auth_type,
-                             conf_key_id=conf_key_id, key=key)
+            bytearray([randint(0, 255) for _ in range(randint(1, 20))])
+        )
+        return VppBFDAuthKey(
+            test=test, auth_type=auth_type, conf_key_id=conf_key_id, key=key
+        )
 
 
 class BFDAPITestCase(VppTestCase):
@@ -87,7 +95,7 @@ class BFDAPITestCase(VppTestCase):
         self.factory = AuthKeyFactory()
 
     def test_add_bfd(self):
-        """ create a BFD session """
+        """create a BFD session"""
         session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
         session.add_vpp_config()
         self.logger.debug("Session state is %s", session.state)
@@ -97,7 +105,7 @@ class BFDAPITestCase(VppTestCase):
         session.remove_vpp_config()
 
     def test_double_add(self):
-        """ create the same BFD session twice (negative case) """
+        """create the same BFD session twice (negative case)"""
         session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
         session.add_vpp_config()
 
@@ -107,9 +115,8 @@ class BFDAPITestCase(VppTestCase):
         session.remove_vpp_config()
 
     def test_add_bfd6(self):
-        """ create IPv6 BFD session """
-        session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6)
+        """create IPv6 BFD session"""
+        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip6, af=AF_INET6)
         session.add_vpp_config()
         self.logger.debug("Session state is %s", session.state)
         session.remove_vpp_config()
@@ -118,65 +125,76 @@ class BFDAPITestCase(VppTestCase):
         session.remove_vpp_config()
 
     def test_mod_bfd(self):
-        """ modify BFD session parameters """
-        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4,
-                                   desired_min_tx=50000,
-                                   required_min_rx=10000,
-                                   detect_mult=1)
+        """modify BFD session parameters"""
+        session = VppBFDUDPSession(
+            self,
+            self.pg0,
+            self.pg0.remote_ip4,
+            desired_min_tx=50000,
+            required_min_rx=10000,
+            detect_mult=1,
+        )
         session.add_vpp_config()
         s = session.get_bfd_udp_session_dump_entry()
-        self.assert_equal(session.desired_min_tx,
-                          s.desired_min_tx,
-                          "desired min transmit interval")
-        self.assert_equal(session.required_min_rx,
-                          s.required_min_rx,
-                          "required min receive interval")
+        self.assert_equal(
+            session.desired_min_tx, s.desired_min_tx, "desired min transmit interval"
+        )
+        self.assert_equal(
+            session.required_min_rx, s.required_min_rx, "required min receive interval"
+        )
         self.assert_equal(session.detect_mult, s.detect_mult, "detect mult")
-        session.modify_parameters(desired_min_tx=session.desired_min_tx * 2,
-                                  required_min_rx=session.required_min_rx * 2,
-                                  detect_mult=session.detect_mult * 2)
+        session.modify_parameters(
+            desired_min_tx=session.desired_min_tx * 2,
+            required_min_rx=session.required_min_rx * 2,
+            detect_mult=session.detect_mult * 2,
+        )
         s = session.get_bfd_udp_session_dump_entry()
-        self.assert_equal(session.desired_min_tx,
-                          s.desired_min_tx,
-                          "desired min transmit interval")
-        self.assert_equal(session.required_min_rx,
-                          s.required_min_rx,
-                          "required min receive interval")
+        self.assert_equal(
+            session.desired_min_tx, s.desired_min_tx, "desired min transmit interval"
+        )
+        self.assert_equal(
+            session.required_min_rx, s.required_min_rx, "required min receive interval"
+        )
         self.assert_equal(session.detect_mult, s.detect_mult, "detect mult")
 
     def test_upd_bfd(self):
-        """ Create/Modify w/ Update BFD session parameters """
-        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4,
-                                   desired_min_tx=50000,
-                                   required_min_rx=10000,
-                                   detect_mult=1)
+        """Create/Modify w/ Update BFD session parameters"""
+        session = VppBFDUDPSession(
+            self,
+            self.pg0,
+            self.pg0.remote_ip4,
+            desired_min_tx=50000,
+            required_min_rx=10000,
+            detect_mult=1,
+        )
         session.upd_vpp_config()
         s = session.get_bfd_udp_session_dump_entry()
-        self.assert_equal(session.desired_min_tx,
-                          s.desired_min_tx,
-                          "desired min transmit interval")
-        self.assert_equal(session.required_min_rx,
-                          s.required_min_rx,
-                          "required min receive interval")
+        self.assert_equal(
+            session.desired_min_tx, s.desired_min_tx, "desired min transmit interval"
+        )
+        self.assert_equal(
+            session.required_min_rx, s.required_min_rx, "required min receive interval"
+        )
 
         self.assert_equal(session.detect_mult, s.detect_mult, "detect mult")
-        session.upd_vpp_config(desired_min_tx=session.desired_min_tx * 2,
-                               required_min_rx=session.required_min_rx * 2,
-                               detect_mult=session.detect_mult * 2)
+        session.upd_vpp_config(
+            desired_min_tx=session.desired_min_tx * 2,
+            required_min_rx=session.required_min_rx * 2,
+            detect_mult=session.detect_mult * 2,
+        )
         s = session.get_bfd_udp_session_dump_entry()
-        self.assert_equal(session.desired_min_tx,
-                          s.desired_min_tx,
-                          "desired min transmit interval")
-        self.assert_equal(session.required_min_rx,
-                          s.required_min_rx,
-                          "required min receive interval")
+        self.assert_equal(
+            session.desired_min_tx, s.desired_min_tx, "desired min transmit interval"
+        )
+        self.assert_equal(
+            session.required_min_rx, s.required_min_rx, "required min receive interval"
+        )
         self.assert_equal(session.detect_mult, s.detect_mult, "detect mult")
 
     def test_add_sha1_keys(self):
-        """ add SHA1 keys """
+        """add SHA1 keys"""
         key_count = 10
-        keys = [self.factory.create_random_key(
-            self) for i in range(0, key_count)]
+        keys = [self.factory.create_random_key(self) for i in range(0, key_count)]
         for key in keys:
             self.assertFalse(key.query_vpp_config())
         for key in keys:
@@ -211,11 +229,10 @@ class BFDAPITestCase(VppTestCase):
             self.assertFalse(key.query_vpp_config())
 
     def test_add_bfd_sha1(self):
-        """ create a BFD session (SHA1) """
+        """create a BFD session (SHA1)"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
-        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4,
-                                   sha1_key=key)
+        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4, sha1_key=key)
         session.add_vpp_config()
         self.logger.debug("Session state is %s", session.state)
         session.remove_vpp_config()
@@ -224,51 +241,56 @@ class BFDAPITestCase(VppTestCase):
         session.remove_vpp_config()
 
     def test_double_add_sha1(self):
-        """ create the same BFD session twice (negative case) (SHA1) """
+        """create the same BFD session twice (negative case) (SHA1)"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
-        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4,
-                                   sha1_key=key)
+        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4, sha1_key=key)
         session.add_vpp_config()
         with self.assertRaises(Exception):
             session.add_vpp_config()
 
     def test_add_auth_nonexistent_key(self):
-        """ create BFD session using non-existent SHA1 (negative case) """
+        """create BFD session using non-existent SHA1 (negative case)"""
         session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4,
-            sha1_key=self.factory.create_random_key(self))
+            self,
+            self.pg0,
+            self.pg0.remote_ip4,
+            sha1_key=self.factory.create_random_key(self),
+        )
         with self.assertRaises(Exception):
             session.add_vpp_config()
 
     def test_shared_sha1_key(self):
-        """ single SHA1 key shared by multiple BFD sessions """
+        """single SHA1 key shared by multiple BFD sessions"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
         sessions = [
-            VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4,
-                             sha1_key=key),
-            VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip6,
-                             sha1_key=key, af=AF_INET6),
-            VppBFDUDPSession(self, self.pg1, self.pg1.remote_ip4,
-                             sha1_key=key),
-            VppBFDUDPSession(self, self.pg1, self.pg1.remote_ip6,
-                             sha1_key=key, af=AF_INET6)]
+            VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4, sha1_key=key),
+            VppBFDUDPSession(
+                self, self.pg0, self.pg0.remote_ip6, sha1_key=key, af=AF_INET6
+            ),
+            VppBFDUDPSession(self, self.pg1, self.pg1.remote_ip4, sha1_key=key),
+            VppBFDUDPSession(
+                self, self.pg1, self.pg1.remote_ip6, sha1_key=key, af=AF_INET6
+            ),
+        ]
         for s in sessions:
             s.add_vpp_config()
         removed = 0
         for s in sessions:
             e = key.get_bfd_auth_keys_dump_entry()
-            self.assert_equal(e.use_count, len(sessions) - removed,
-                              "Use count for shared key")
+            self.assert_equal(
+                e.use_count, len(sessions) - removed, "Use count for shared key"
+            )
             s.remove_vpp_config()
             removed += 1
         e = key.get_bfd_auth_keys_dump_entry()
-        self.assert_equal(e.use_count, len(sessions) - removed,
-                          "Use count for shared key")
+        self.assert_equal(
+            e.use_count, len(sessions) - removed, "Use count for shared key"
+        )
 
     def test_activate_auth(self):
-        """ activate SHA1 authentication """
+        """activate SHA1 authentication"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
         session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
@@ -276,7 +298,7 @@ class BFDAPITestCase(VppTestCase):
         session.activate_auth(key)
 
     def test_deactivate_auth(self):
-        """ deactivate SHA1 authentication """
+        """deactivate SHA1 authentication"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
         session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
@@ -285,20 +307,19 @@ class BFDAPITestCase(VppTestCase):
         session.deactivate_auth()
 
     def test_change_key(self):
-        """ change SHA1 key """
+        """change SHA1 key"""
         key1 = self.factory.create_random_key(self)
         key2 = self.factory.create_random_key(self)
         while key2.conf_key_id == key1.conf_key_id:
             key2 = self.factory.create_random_key(self)
         key1.add_vpp_config()
         key2.add_vpp_config()
-        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4,
-                                   sha1_key=key1)
+        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4, sha1_key=key1)
         session.add_vpp_config()
         session.activate_auth(key2)
 
     def test_set_del_udp_echo_source(self):
-        """ set/del udp echo source """
+        """set/del udp echo source"""
         self.create_loopback_interfaces(1)
         self.loopback0 = self.lo_interfaces[0]
         self.loopback0.admin_up()
@@ -307,8 +328,7 @@ class BFDAPITestCase(VppTestCase):
         self.assertFalse(echo_source.have_usable_ip4)
         self.assertFalse(echo_source.have_usable_ip6)
 
-        self.vapi.bfd_udp_set_echo_source(
-            sw_if_index=self.loopback0.sw_if_index)
+        self.vapi.bfd_udp_set_echo_source(sw_if_index=self.loopback0.sw_if_index)
         echo_source = self.vapi.bfd_udp_get_echo_source()
         self.assertTrue(echo_source.is_set)
         self.assertEqual(echo_source.sw_if_index, self.loopback0.sw_if_index)
@@ -316,8 +336,9 @@ class BFDAPITestCase(VppTestCase):
         self.assertFalse(echo_source.have_usable_ip6)
 
         self.loopback0.config_ip4()
-        echo_ip4 = ipaddress.IPv4Address(int(ipaddress.IPv4Address(
-            self.loopback0.local_ip4)) ^ 1).packed
+        echo_ip4 = ipaddress.IPv4Address(
+            int(ipaddress.IPv4Address(self.loopback0.local_ip4)) ^ 1
+        ).packed
         echo_source = self.vapi.bfd_udp_get_echo_source()
         self.assertTrue(echo_source.is_set)
         self.assertEqual(echo_source.sw_if_index, self.loopback0.sw_if_index)
@@ -326,8 +347,9 @@ class BFDAPITestCase(VppTestCase):
         self.assertFalse(echo_source.have_usable_ip6)
 
         self.loopback0.config_ip6()
-        echo_ip6 = ipaddress.IPv6Address(int(ipaddress.IPv6Address(
-            self.loopback0.local_ip6)) ^ 1).packed
+        echo_ip6 = ipaddress.IPv6Address(
+            int(ipaddress.IPv6Address(self.loopback0.local_ip6)) ^ 1
+        ).packed
 
         echo_source = self.vapi.bfd_udp_get_echo_source()
         self.assertTrue(echo_source.is_set)
@@ -345,11 +367,20 @@ class BFDAPITestCase(VppTestCase):
 
 
 class BFDTestSession(object):
-    """ BFD session as seen from test framework side """
-
-    def __init__(self, test, interface, af, detect_mult=3, sha1_key=None,
-                 bfd_key_id=None, our_seq_number=None,
-                 tunnel_header=None, phy_interface=None):
+    """BFD session as seen from test framework side"""
+
+    def __init__(
+        self,
+        test,
+        interface,
+        af,
+        detect_mult=3,
+        sha1_key=None,
+        bfd_key_id=None,
+        our_seq_number=None,
+        tunnel_header=None,
+        phy_interface=None,
+    ):
         self.test = test
         self.af = af
         self.sha1_key = sha1_key
@@ -381,17 +412,25 @@ class BFDTestSession(object):
         self.rx_packets_echo = 0
 
     def inc_seq_num(self):
-        """ increment sequence number, wrapping if needed """
+        """increment sequence number, wrapping if needed"""
         if self.our_seq_number == 0xFFFFFFFF:
             self.our_seq_number = 0
         else:
             self.our_seq_number += 1
 
-    def update(self, my_discriminator=None, your_discriminator=None,
-               desired_min_tx=None, required_min_rx=None,
-               required_min_echo_rx=None, detect_mult=None,
-               diag=None, state=None, auth_type=None):
-        """ update BFD parameters associated with session """
+    def update(
+        self,
+        my_discriminator=None,
+        your_discriminator=None,
+        desired_min_tx=None,
+        required_min_rx=None,
+        required_min_echo_rx=None,
+        detect_mult=None,
+        diag=None,
+        state=None,
+        auth_type=None,
+    ):
+        """update BFD parameters associated with session"""
         if my_discriminator is not None:
             self.my_discriminator = my_discriminator
         if your_discriminator is not None:
@@ -412,34 +451,37 @@ class BFDTestSession(object):
             self.auth_type = auth_type
 
     def fill_packet_fields(self, packet):
-        """ set packet fields with known values in packet """
+        """set packet fields with known values in packet"""
         bfd = packet[BFD]
         if self.my_discriminator:
-            self.test.logger.debug("BFD: setting packet.my_discriminator=%s",
-                                   self.my_discriminator)
+            self.test.logger.debug(
+                "BFD: setting packet.my_discriminator=%s", self.my_discriminator
+            )
             bfd.my_discriminator = self.my_discriminator
         if self.your_discriminator:
-            self.test.logger.debug("BFD: setting packet.your_discriminator=%s",
-                                   self.your_discriminator)
+            self.test.logger.debug(
+                "BFD: setting packet.your_discriminator=%s", self.your_discriminator
+            )
             bfd.your_discriminator = self.your_discriminator
         if self.required_min_rx:
             self.test.logger.debug(
-                "BFD: setting packet.required_min_rx_interval=%s",
-                self.required_min_rx)
+                "BFD: setting packet.required_min_rx_interval=%s", self.required_min_rx
+            )
             bfd.required_min_rx_interval = self.required_min_rx
         if self.required_min_echo_rx:
             self.test.logger.debug(
-                "BFD: setting packet.required_min_echo_rx=%s",
-                self.required_min_echo_rx)
+                "BFD: setting packet.required_min_echo_rx=%s", self.required_min_echo_rx
+            )
             bfd.required_min_echo_rx_interval = self.required_min_echo_rx
         if self.desired_min_tx:
             self.test.logger.debug(
-                "BFD: setting packet.desired_min_tx_interval=%s",
-                self.desired_min_tx)
+                "BFD: setting packet.desired_min_tx_interval=%s", self.desired_min_tx
+            )
             bfd.desired_min_tx_interval = self.desired_min_tx
         if self.detect_mult:
             self.test.logger.debug(
-                "BFD: setting packet.detect_mult=%s", self.detect_mult)
+                "BFD: setting packet.detect_mult=%s", self.detect_mult
+            )
             bfd.detect_mult = self.detect_mult
         if self.diag:
             self.test.logger.debug("BFD: setting packet.diag=%s", self.diag)
@@ -449,12 +491,11 @@ class BFDTestSession(object):
             bfd.state = self.state
         if self.auth_type:
             # this is used by a negative test-case
-            self.test.logger.debug("BFD: setting packet.auth_type=%s",
-                                   self.auth_type)
+            self.test.logger.debug("BFD: setting packet.auth_type=%s", self.auth_type)
             bfd.auth_type = self.auth_type
 
     def create_packet(self):
-        """ create a BFD packet, reflecting the current state of session """
+        """create a BFD packet, reflecting the current state of session"""
         if self.sha1_key:
             bfd = BFD(flags="A")
             bfd.auth_type = self.sha1_key.auth_type
@@ -464,37 +505,48 @@ class BFDTestSession(object):
             bfd.length = BFD.sha1_auth_len + BFD.bfd_pkt_len
         else:
             bfd = BFD()
-        packet = Ether(src=self.phy_interface.remote_mac,
-                       dst=self.phy_interface.local_mac)
+        packet = Ether(
+            src=self.phy_interface.remote_mac, dst=self.phy_interface.local_mac
+        )
         if self.tunnel_header:
             packet = packet / self.tunnel_header
         if self.af == AF_INET6:
-            packet = (packet /
-                      IPv6(src=self.interface.remote_ip6,
-                           dst=self.interface.local_ip6,
-                           hlim=255) /
-                      UDP(sport=self.udp_sport, dport=BFD.udp_dport) /
-                      bfd)
+            packet = (
+                packet
+                / IPv6(
+                    src=self.interface.remote_ip6,
+                    dst=self.interface.local_ip6,
+                    hlim=255,
+                )
+                / UDP(sport=self.udp_sport, dport=BFD.udp_dport)
+                / bfd
+            )
         else:
-            packet = (packet /
-                      IP(src=self.interface.remote_ip4,
-                         dst=self.interface.local_ip4,
-                         ttl=255) /
-                      UDP(sport=self.udp_sport, dport=BFD.udp_dport) /
-                      bfd)
+            packet = (
+                packet
+                / IP(
+                    src=self.interface.remote_ip4, dst=self.interface.local_ip4, ttl=255
+                )
+                / UDP(sport=self.udp_sport, dport=BFD.udp_dport)
+                / bfd
+            )
         self.test.logger.debug("BFD: Creating packet")
         self.fill_packet_fields(packet)
         if self.sha1_key:
-            hash_material = scapy.compat.raw(
-                packet[BFD])[:32] + self.sha1_key.key + \
-                b"\0" * (20 - len(self.sha1_key.key))
-            self.test.logger.debug("BFD: Calculated SHA1 hash: %s" %
-                                   hashlib.sha1(hash_material).hexdigest())
+            hash_material = (
+                scapy.compat.raw(packet[BFD])[:32]
+                + self.sha1_key.key
+                + b"\0" * (20 - len(self.sha1_key.key))
+            )
+            self.test.logger.debug(
+                "BFD: Calculated SHA1 hash: %s"
+                % hashlib.sha1(hash_material).hexdigest()
+            )
             packet[BFD].auth_key_hash = hashlib.sha1(hash_material).digest()
         return packet
 
     def send_packet(self, packet=None, interface=None):
-        """ send packet on interface, creating the packet if needed """
+        """send packet on interface, creating the packet if needed"""
         if packet is None:
             packet = self.create_packet()
         if interface is None:
@@ -505,82 +557,95 @@ class BFDTestSession(object):
         self.test.pg_start()
 
     def verify_sha1_auth(self, packet):
-        """ Verify correctness of authentication in BFD layer. """
+        """Verify correctness of authentication in BFD layer."""
         bfd = packet[BFD]
         self.test.assert_equal(bfd.auth_len, 28, "Auth section length")
-        self.test.assert_equal(bfd.auth_type, self.sha1_key.auth_type,
-                               BFDAuthType)
+        self.test.assert_equal(bfd.auth_type, self.sha1_key.auth_type, BFDAuthType)
         self.test.assert_equal(bfd.auth_key_id, self.bfd_key_id, "Key ID")
         self.test.assert_equal(bfd.auth_reserved, 0, "Reserved")
         if self.vpp_seq_number is None:
             self.vpp_seq_number = bfd.auth_seq_num
-            self.test.logger.debug("Received initial sequence number: %s" %
-                                   self.vpp_seq_number)
+            self.test.logger.debug(
+                "Received initial sequence number: %s" % self.vpp_seq_number
+            )
         else:
             recvd_seq_num = bfd.auth_seq_num
-            self.test.logger.debug("Received followup sequence number: %s" %
-                                   recvd_seq_num)
-            if self.vpp_seq_number < 0xffffffff:
-                if self.sha1_key.auth_type == \
-                        BFDAuthType.meticulous_keyed_sha1:
-                    self.test.assert_equal(recvd_seq_num,
-                                           self.vpp_seq_number + 1,
-                                           "BFD sequence number")
+            self.test.logger.debug(
+                "Received followup sequence number: %s" % recvd_seq_num
+            )
+            if self.vpp_seq_number < 0xFFFFFFFF:
+                if self.sha1_key.auth_type == BFDAuthType.meticulous_keyed_sha1:
+                    self.test.assert_equal(
+                        recvd_seq_num, self.vpp_seq_number + 1, "BFD sequence number"
+                    )
                 else:
-                    self.test.assert_in_range(recvd_seq_num,
-                                              self.vpp_seq_number,
-                                              self.vpp_seq_number + 1,
-                                              "BFD sequence number")
+                    self.test.assert_in_range(
+                        recvd_seq_num,
+                        self.vpp_seq_number,
+                        self.vpp_seq_number + 1,
+                        "BFD sequence number",
+                    )
             else:
-                if self.sha1_key.auth_type == \
-                        BFDAuthType.meticulous_keyed_sha1:
-                    self.test.assert_equal(recvd_seq_num, 0,
-                                           "BFD sequence number")
+                if self.sha1_key.auth_type == BFDAuthType.meticulous_keyed_sha1:
+                    self.test.assert_equal(recvd_seq_num, 0, "BFD sequence number")
                 else:
-                    self.test.assertIn(recvd_seq_num, (self.vpp_seq_number, 0),
-                                       "BFD sequence number not one of "
-                                       "(%s, 0)" % self.vpp_seq_number)
+                    self.test.assertIn(
+                        recvd_seq_num,
+                        (self.vpp_seq_number, 0),
+                        "BFD sequence number not one of "
+                        "(%s, 0)" % self.vpp_seq_number,
+                    )
             self.vpp_seq_number = recvd_seq_num
         # last 20 bytes represent the hash - so replace them with the key,
         # pad the result with zeros and hash the result
-        hash_material = bfd.original[:-20] + self.sha1_key.key + \
-            b"\0" * (20 - len(self.sha1_key.key))
+        hash_material = (
+            bfd.original[:-20]
+            + self.sha1_key.key
+            + b"\0" * (20 - len(self.sha1_key.key))
+        )
         expected_hash = hashlib.sha1(hash_material).hexdigest()
-        self.test.assert_equal(binascii.hexlify(bfd.auth_key_hash),
-                               expected_hash.encode(), "Auth key hash")
+        self.test.assert_equal(
+            binascii.hexlify(bfd.auth_key_hash), expected_hash.encode(), "Auth key hash"
+        )
 
     def verify_bfd(self, packet):
-        """ Verify correctness of BFD layer. """
+        """Verify correctness of BFD layer."""
         bfd = packet[BFD]
         self.test.assert_equal(bfd.version, 1, "BFD version")
-        self.test.assert_equal(bfd.your_discriminator,
-                               self.my_discriminator,
-                               "BFD - your discriminator")
+        self.test.assert_equal(
+            bfd.your_discriminator, self.my_discriminator, "BFD - your discriminator"
+        )
         if self.sha1_key:
             self.verify_sha1_auth(packet)
 
 
 def bfd_session_up(test):
-    """ Bring BFD session up """
+    """Bring BFD session up"""
     test.logger.info("BFD: Waiting for slow hello")
     p = wait_for_bfd_packet(test, 2, is_tunnel=test.vpp_session.is_tunnel)
     old_offset = None
-    if hasattr(test, 'vpp_clock_offset'):
+    if hasattr(test, "vpp_clock_offset"):
         old_offset = test.vpp_clock_offset
     test.vpp_clock_offset = time.time() - float(p.time)
-    test.logger.debug("BFD: Calculated vpp clock offset: %s",
-                      test.vpp_clock_offset)
+    test.logger.debug("BFD: Calculated vpp clock offset: %s", test.vpp_clock_offset)
     if old_offset:
         test.assertAlmostEqual(
-            old_offset, test.vpp_clock_offset, delta=0.5,
-            msg="vpp clock offset not stable (new: %s, old: %s)" %
-            (test.vpp_clock_offset, old_offset))
+            old_offset,
+            test.vpp_clock_offset,
+            delta=0.5,
+            msg="vpp clock offset not stable (new: %s, old: %s)"
+            % (test.vpp_clock_offset, old_offset),
+        )
     test.logger.info("BFD: Sending Init")
-    test.test_session.update(my_discriminator=randint(0, 40000000),
-                             your_discriminator=p[BFD].my_discriminator,
-                             state=BFDState.init)
-    if test.test_session.sha1_key and test.test_session.sha1_key.auth_type == \
-            BFDAuthType.meticulous_keyed_sha1:
+    test.test_session.update(
+        my_discriminator=randint(0, 40000000),
+        your_discriminator=p[BFD].my_discriminator,
+        state=BFDState.init,
+    )
+    if (
+        test.test_session.sha1_key
+        and test.test_session.sha1_key.auth_type == BFDAuthType.meticulous_keyed_sha1
+    ):
         test.test_session.inc_seq_num()
     test.test_session.send_packet()
     test.logger.info("BFD: Waiting for event")
@@ -588,19 +653,23 @@ def bfd_session_up(test):
     verify_event(test, e, expected_state=BFDState.up)
     test.logger.info("BFD: Session is Up")
     test.test_session.update(state=BFDState.up)
-    if test.test_session.sha1_key and test.test_session.sha1_key.auth_type == \
-            BFDAuthType.meticulous_keyed_sha1:
+    if (
+        test.test_session.sha1_key
+        and test.test_session.sha1_key.auth_type == BFDAuthType.meticulous_keyed_sha1
+    ):
         test.test_session.inc_seq_num()
     test.test_session.send_packet()
     test.assert_equal(test.vpp_session.state, BFDState.up, BFDState)
 
 
 def bfd_session_down(test):
-    """ Bring BFD session down """
+    """Bring BFD session down"""
     test.assert_equal(test.vpp_session.state, BFDState.up, BFDState)
     test.test_session.update(state=BFDState.down)
-    if test.test_session.sha1_key and test.test_session.sha1_key.auth_type == \
-            BFDAuthType.meticulous_keyed_sha1:
+    if (
+        test.test_session.sha1_key
+        and test.test_session.sha1_key.auth_type == BFDAuthType.meticulous_keyed_sha1
+    ):
         test.test_session.inc_seq_num()
     test.test_session.send_packet()
     test.logger.info("BFD: Waiting for event")
@@ -617,25 +686,25 @@ def verify_bfd_session_config(test, session, state=None):
     # are valid (in get_bfd_udp_session_dump_entry)
     if state:
         test.assert_equal(dump.state, state, "session state")
-    test.assert_equal(dump.required_min_rx, session.required_min_rx,
-                      "required min rx interval")
-    test.assert_equal(dump.desired_min_tx, session.desired_min_tx,
-                      "desired min tx interval")
-    test.assert_equal(dump.detect_mult, session.detect_mult,
-                      "detect multiplier")
+    test.assert_equal(
+        dump.required_min_rx, session.required_min_rx, "required min rx interval"
+    )
+    test.assert_equal(
+        dump.desired_min_tx, session.desired_min_tx, "desired min tx interval"
+    )
+    test.assert_equal(dump.detect_mult, session.detect_mult, "detect multiplier")
     if session.sha1_key is None:
         test.assert_equal(dump.is_authenticated, 0, "is_authenticated flag")
     else:
         test.assert_equal(dump.is_authenticated, 1, "is_authenticated flag")
-        test.assert_equal(dump.bfd_key_id, session.bfd_key_id,
-                          "bfd key id")
-        test.assert_equal(dump.conf_key_id,
-                          session.sha1_key.conf_key_id,
-                          "config key id")
+        test.assert_equal(dump.bfd_key_id, session.bfd_key_id, "bfd key id")
+        test.assert_equal(
+            dump.conf_key_id, session.sha1_key.conf_key_id, "config key id"
+        )
 
 
 def verify_ip(test, packet):
-    """ Verify correctness of IP layer. """
+    """Verify correctness of IP layer."""
     if test.vpp_session.af == AF_INET6:
         ip = packet[IPv6]
         local_ip = test.vpp_session.interface.local_ip6
@@ -651,30 +720,31 @@ def verify_ip(test, packet):
 
 
 def verify_udp(test, packet):
-    """ Verify correctness of UDP layer. """
+    """Verify correctness of UDP layer."""
     udp = packet[UDP]
     test.assert_equal(udp.dport, BFD.udp_dport, "UDP destination port")
-    test.assert_in_range(udp.sport, BFD.udp_sport_min, BFD.udp_sport_max,
-                         "UDP source port")
+    test.assert_in_range(
+        udp.sport, BFD.udp_sport_min, BFD.udp_sport_max, "UDP source port"
+    )
 
 
 def verify_event(test, event, expected_state):
-    """ Verify correctness of event values. """
+    """Verify correctness of event values."""
     e = event
     test.logger.debug("BFD: Event: %s" % reprlib.repr(e))
-    test.assert_equal(e.sw_if_index,
-                      test.vpp_session.interface.sw_if_index,
-                      "BFD interface index")
-
-    test.assert_equal(str(e.local_addr), test.vpp_session.local_addr,
-                      "Local IPv6 address")
-    test.assert_equal(str(e.peer_addr), test.vpp_session.peer_addr,
-                      "Peer IPv6 address")
+    test.assert_equal(
+        e.sw_if_index, test.vpp_session.interface.sw_if_index, "BFD interface index"
+    )
+
+    test.assert_equal(
+        str(e.local_addr), test.vpp_session.local_addr, "Local IPv6 address"
+    )
+    test.assert_equal(str(e.peer_addr), test.vpp_session.peer_addr, "Peer IPv6 address")
     test.assert_equal(e.state, expected_state, BFDState)
 
 
 def wait_for_bfd_packet(test, timeout=1, pcap_time_min=None, is_tunnel=False):
-    """ wait for BFD packet and verify its correctness
+    """wait for BFD packet and verify its correctness
 
     :param timeout: how long to wait
     :param pcap_time_min: ignore packets with pcap timestamp lower than this
@@ -695,9 +765,13 @@ def wait_for_bfd_packet(test, timeout=1, pcap_time_min=None, is_tunnel=False):
         test.test_session.rx_packets += 1
         test.logger.debug(ppp("BFD: Got packet:", p))
         if pcap_time_min is not None and p.time < pcap_time_min:
-            test.logger.debug(ppp("BFD: ignoring packet (pcap time %s < "
-                                  "pcap time min %s):" %
-                                  (p.time, pcap_time_min), p))
+            test.logger.debug(
+                ppp(
+                    "BFD: ignoring packet (pcap time %s < "
+                    "pcap time min %s):" % (p.time, pcap_time_min),
+                    p,
+                )
+            )
         else:
             break
     if is_tunnel:
@@ -722,15 +796,15 @@ def bfd_grab_stats_snapshot(test, bs_idx=0, thread_index=None):
     s = test.statistics
     ti = thread_index
     if ti is None:
-        rx = s['/bfd/rx-session-counters'][:, bs_idx].sum_packets()
-        rx_echo = s['/bfd/rx-session-echo-counters'][:, bs_idx].sum_packets()
-        tx = s['/bfd/tx-session-counters'][:, bs_idx].sum_packets()
-        tx_echo = s['/bfd/tx-session-echo-counters'][:, bs_idx].sum_packets()
+        rx = s["/bfd/rx-session-counters"][:, bs_idx].sum_packets()
+        rx_echo = s["/bfd/rx-session-echo-counters"][:, bs_idx].sum_packets()
+        tx = s["/bfd/tx-session-counters"][:, bs_idx].sum_packets()
+        tx_echo = s["/bfd/tx-session-echo-counters"][:, bs_idx].sum_packets()
     else:
-        rx = s['/bfd/rx-session-counters'][ti, bs_idx].sum_packets()
-        rx_echo = s['/bfd/rx-session-echo-counters'][ti, bs_idx].sum_packets()
-        tx = s['/bfd/tx-session-counters'][ti, bs_idx].sum_packets()
-        tx_echo = s['/bfd/tx-session-echo-counters'][ti, bs_idx].sum_packets()
+        rx = s["/bfd/rx-session-counters"][ti, bs_idx].sum_packets()
+        rx_echo = s["/bfd/rx-session-echo-counters"][ti, bs_idx].sum_packets()
+        tx = s["/bfd/tx-session-counters"][ti, bs_idx].sum_packets()
+        tx_echo = s["/bfd/tx-session-echo-counters"][ti, bs_idx].sum_packets()
     return BFDStats(rx, rx_echo, tx, tx_echo)
 
 
@@ -780,10 +854,9 @@ class BFD4TestCase(VppTestCase):
         self.vapi.want_bfd_events()
         self.pg0.enable_capture()
         try:
-            self.bfd_udp4_sessions = self.statistics['/bfd/udp4/sessions']
-            self.bfd_udp6_sessions = self.statistics['/bfd/udp6/sessions']
-            self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                                self.pg0.remote_ip4)
+            self.bfd_udp4_sessions = self.statistics["/bfd/udp4/sessions"]
+            self.bfd_udp6_sessions = self.statistics["/bfd/udp6/sessions"]
+            self.vpp_session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
             self.vpp_session.add_vpp_config()
             self.vpp_session.admin_up()
             self.test_session = BFDTestSession(self, self.pg0, AF_INET)
@@ -798,26 +871,29 @@ class BFD4TestCase(VppTestCase):
         super(BFD4TestCase, self).tearDown()
 
     def test_session_up(self):
-        """ bring BFD session up """
+        """bring BFD session up"""
         bfd_session_up(self)
-        bfd_udp4_sessions = self.statistics['/bfd/udp4/sessions']
-        bfd_udp6_sessions = self.statistics['/bfd/udp6/sessions']
+        bfd_udp4_sessions = self.statistics["/bfd/udp4/sessions"]
+        bfd_udp6_sessions = self.statistics["/bfd/udp6/sessions"]
         self.assert_equal(bfd_udp4_sessions - self.bfd_udp4_sessions, 1)
         self.assert_equal(bfd_udp6_sessions, self.bfd_udp6_sessions)
 
     def test_session_up_by_ip(self):
-        """ bring BFD session up - first frame looked up by address pair """
+        """bring BFD session up - first frame looked up by address pair"""
         self.logger.info("BFD: Sending Slow control frame")
         self.test_session.update(my_discriminator=randint(0, 40000000))
         self.test_session.send_packet()
         self.pg0.enable_capture()
         p = self.pg0.wait_for_packet(1)
-        self.assert_equal(p[BFD].your_discriminator,
-                          self.test_session.my_discriminator,
-                          "BFD - your discriminator")
+        self.assert_equal(
+            p[BFD].your_discriminator,
+            self.test_session.my_discriminator,
+            "BFD - your discriminator",
+        )
         self.assert_equal(p[BFD].state, BFDState.init, BFDState)
-        self.test_session.update(your_discriminator=p[BFD].my_discriminator,
-                                 state=BFDState.up)
+        self.test_session.update(
+            your_discriminator=p[BFD].my_discriminator, state=BFDState.up
+        )
         self.logger.info("BFD: Waiting for event")
         e = self.vapi.wait_for_event(1, "bfd_udp_session_event")
         verify_event(self, e, expected_state=BFDState.init)
@@ -832,21 +908,20 @@ class BFD4TestCase(VppTestCase):
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
 
     def test_session_down(self):
-        """ bring BFD session down """
+        """bring BFD session down"""
         bfd_session_up(self)
         bfd_session_down(self)
 
     def test_hold_up(self):
-        """ hold BFD session up """
+        """hold BFD session up"""
         bfd_session_up(self)
         for dummy in range(self.test_session.detect_mult * 2):
             wait_for_bfd_packet(self)
             self.test_session.send_packet()
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
 
     def test_slow_timer(self):
-        """ verify slow periodic control frames while session down """
+        """verify slow periodic control frames while session down"""
         packet_count = 3
         self.logger.info("BFD: Waiting for %d BFD packets", packet_count)
         prev_packet = wait_for_bfd_packet(self, 2)
@@ -855,55 +930,60 @@ class BFD4TestCase(VppTestCase):
             time_diff = next_packet.time - prev_packet.time
             # spec says the range should be <0.75, 1>, allow extra 0.05 margin
             # to work around timing issues
-            self.assert_in_range(
-                time_diff, 0.70, 1.05, "time between slow packets")
+            self.assert_in_range(time_diff, 0.70, 1.05, "time between slow packets")
             prev_packet = next_packet
 
     def test_zero_remote_min_rx(self):
-        """ no packets when zero remote required min rx interval """
+        """no packets when zero remote required min rx interval"""
         bfd_session_up(self)
         self.test_session.update(required_min_rx=0)
         self.test_session.send_packet()
         for dummy in range(self.test_session.detect_mult):
-            self.sleep(self.vpp_session.required_min_rx / USEC_IN_SEC,
-                       "sleep before transmitting bfd packet")
+            self.sleep(
+                self.vpp_session.required_min_rx / USEC_IN_SEC,
+                "sleep before transmitting bfd packet",
+            )
             self.test_session.send_packet()
             try:
                 p = wait_for_bfd_packet(self, timeout=0)
                 self.logger.error(ppp("Received unexpected packet:", p))
             except CaptureTimeoutError:
                 pass
-        self.assert_equal(
-            len(self.vapi.collect_events()), 0, "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
         self.test_session.update(required_min_rx=300000)
         for dummy in range(3):
             self.test_session.send_packet()
             wait_for_bfd_packet(
-                self, timeout=self.test_session.required_min_rx / USEC_IN_SEC)
-        self.assert_equal(
-            len(self.vapi.collect_events()), 0, "number of bfd events")
+                self, timeout=self.test_session.required_min_rx / USEC_IN_SEC
+            )
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
 
     def test_conn_down(self):
-        """ verify session goes down after inactivity """
+        """verify session goes down after inactivity"""
         bfd_session_up(self)
-        detection_time = self.test_session.detect_mult *\
-            self.vpp_session.required_min_rx / USEC_IN_SEC
+        detection_time = (
+            self.test_session.detect_mult
+            * self.vpp_session.required_min_rx
+            / USEC_IN_SEC
+        )
         self.sleep(detection_time, "waiting for BFD session time-out")
         e = self.vapi.wait_for_event(1, "bfd_udp_session_event")
         verify_event(self, e, expected_state=BFDState.down)
 
     def test_peer_discr_reset_sess_down(self):
-        """ peer discriminator reset after session goes down """
+        """peer discriminator reset after session goes down"""
         bfd_session_up(self)
-        detection_time = self.test_session.detect_mult *\
-            self.vpp_session.required_min_rx / USEC_IN_SEC
+        detection_time = (
+            self.test_session.detect_mult
+            * self.vpp_session.required_min_rx
+            / USEC_IN_SEC
+        )
         self.sleep(detection_time, "waiting for BFD session time-out")
         self.test_session.my_discriminator = 0
-        wait_for_bfd_packet(self,
-                            pcap_time_min=time.time() - self.vpp_clock_offset)
+        wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
 
     def test_large_required_min_rx(self):
-        """ large remote required min rx interval """
+        """large remote required min rx interval"""
         bfd_session_up(self)
         p = wait_for_bfd_packet(self)
         interval = 3000000
@@ -932,14 +1012,14 @@ class BFD4TestCase(VppTestCase):
         self.assert_equal(count, 0, "number of packets received")
 
     def test_immediate_remote_min_rx_reduction(self):
-        """ immediately honor remote required min rx reduction """
+        """immediately honor remote required min rx reduction"""
         self.vpp_session.remove_vpp_config()
         self.vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4, desired_min_tx=10000)
+            self, self.pg0, self.pg0.remote_ip4, desired_min_tx=10000
+        )
         self.pg0.enable_capture()
         self.vpp_session.add_vpp_config()
-        self.test_session.update(desired_min_tx=1000000,
-                                 required_min_rx=1000000)
+        self.test_session.update(desired_min_tx=1000000, required_min_rx=1000000)
         bfd_session_up(self)
         reference_packet = wait_for_bfd_packet(self)
         time_mark = time.time()
@@ -950,131 +1030,143 @@ class BFD4TestCase(VppTestCase):
         p = wait_for_bfd_packet(self)
         # first packet is allowed to be late by time we spent doing the update
         # calculated in extra_time
-        self.assert_in_range(p.time - reference_packet.time,
-                             .95 * 0.75 * interval / USEC_IN_SEC,
-                             1.05 * interval / USEC_IN_SEC + extra_time,
-                             "time between BFD packets")
+        self.assert_in_range(
+            p.time - reference_packet.time,
+            0.95 * 0.75 * interval / USEC_IN_SEC,
+            1.05 * interval / USEC_IN_SEC + extra_time,
+            "time between BFD packets",
+        )
         reference_packet = p
         for dummy in range(3):
             p = wait_for_bfd_packet(self)
             diff = p.time - reference_packet.time
-            self.assert_in_range(diff, .95 * .75 * interval / USEC_IN_SEC,
-                                 1.05 * interval / USEC_IN_SEC,
-                                 "time between BFD packets")
+            self.assert_in_range(
+                diff,
+                0.95 * 0.75 * interval / USEC_IN_SEC,
+                1.05 * interval / USEC_IN_SEC,
+                "time between BFD packets",
+            )
             reference_packet = p
 
     def test_modify_req_min_rx_double(self):
-        """ modify session - double required min rx """
+        """modify session - double required min rx"""
         bfd_session_up(self)
         p = wait_for_bfd_packet(self)
-        self.test_session.update(desired_min_tx=10000,
-                                 required_min_rx=10000)
+        self.test_session.update(desired_min_tx=10000, required_min_rx=10000)
         self.test_session.send_packet()
         # double required min rx
         self.vpp_session.modify_parameters(
-            required_min_rx=2 * self.vpp_session.required_min_rx)
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
+            required_min_rx=2 * self.vpp_session.required_min_rx
+        )
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
         # poll bit needs to be set
-        self.assertIn("P", p.sprintf("%BFD.flags%"),
-                      "Poll bit not set in BFD packet")
+        self.assertIn("P", p.sprintf("%BFD.flags%"), "Poll bit not set in BFD packet")
         # finish poll sequence with final packet
         final = self.test_session.create_packet()
         final[BFD].flags = "F"
-        timeout = self.test_session.detect_mult * \
-            max(self.test_session.desired_min_tx,
-                self.vpp_session.required_min_rx) / USEC_IN_SEC
+        timeout = (
+            self.test_session.detect_mult
+            * max(self.test_session.desired_min_tx, self.vpp_session.required_min_rx)
+            / USEC_IN_SEC
+        )
         self.test_session.send_packet(final)
         time_mark = time.time()
         e = self.vapi.wait_for_event(2 * timeout, "bfd_udp_session_event")
         verify_event(self, e, expected_state=BFDState.down)
         time_to_event = time.time() - time_mark
-        self.assert_in_range(time_to_event, .9 * timeout,
-                             1.1 * timeout, "session timeout")
+        self.assert_in_range(
+            time_to_event, 0.9 * timeout, 1.1 * timeout, "session timeout"
+        )
 
     def test_modify_req_min_rx_halve(self):
-        """ modify session - halve required min rx """
+        """modify session - halve required min rx"""
         self.vpp_session.modify_parameters(
-            required_min_rx=2 * self.vpp_session.required_min_rx)
+            required_min_rx=2 * self.vpp_session.required_min_rx
+        )
         bfd_session_up(self)
         p = wait_for_bfd_packet(self)
-        self.test_session.update(desired_min_tx=10000,
-                                 required_min_rx=10000)
+        self.test_session.update(desired_min_tx=10000, required_min_rx=10000)
         self.test_session.send_packet()
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
         # halve required min rx
         old_required_min_rx = self.vpp_session.required_min_rx
         self.vpp_session.modify_parameters(
-            required_min_rx=self.vpp_session.required_min_rx // 2)
+            required_min_rx=self.vpp_session.required_min_rx // 2
+        )
         # now we wait 0.8*3*old-req-min-rx and the session should still be up
-        self.sleep(0.8 * self.vpp_session.detect_mult *
-                   old_required_min_rx / USEC_IN_SEC,
-                   "wait before finishing poll sequence")
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.sleep(
+            0.8 * self.vpp_session.detect_mult * old_required_min_rx / USEC_IN_SEC,
+            "wait before finishing poll sequence",
+        )
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
         p = wait_for_bfd_packet(self)
         # poll bit needs to be set
-        self.assertIn("P", p.sprintf("%BFD.flags%"),
-                      "Poll bit not set in BFD packet")
+        self.assertIn("P", p.sprintf("%BFD.flags%"), "Poll bit not set in BFD packet")
         # finish poll sequence with final packet
         final = self.test_session.create_packet()
         final[BFD].flags = "F"
         self.test_session.send_packet(final)
         # now the session should time out under new conditions
-        detection_time = self.test_session.detect_mult *\
-            self.vpp_session.required_min_rx / USEC_IN_SEC
+        detection_time = (
+            self.test_session.detect_mult
+            * self.vpp_session.required_min_rx
+            / USEC_IN_SEC
+        )
         before = time.time()
-        e = self.vapi.wait_for_event(
-            2 * detection_time, "bfd_udp_session_event")
+        e = self.vapi.wait_for_event(2 * detection_time, "bfd_udp_session_event")
         after = time.time()
-        self.assert_in_range(after - before,
-                             0.9 * detection_time,
-                             1.1 * detection_time,
-                             "time before bfd session goes down")
+        self.assert_in_range(
+            after - before,
+            0.9 * detection_time,
+            1.1 * detection_time,
+            "time before bfd session goes down",
+        )
         verify_event(self, e, expected_state=BFDState.down)
 
     def test_modify_detect_mult(self):
-        """ modify detect multiplier """
+        """modify detect multiplier"""
         bfd_session_up(self)
         p = wait_for_bfd_packet(self)
         self.vpp_session.modify_parameters(detect_mult=1)
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
-        self.assert_equal(self.vpp_session.detect_mult,
-                          p[BFD].detect_mult,
-                          "detect mult")
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
+        self.assert_equal(
+            self.vpp_session.detect_mult, p[BFD].detect_mult, "detect mult"
+        )
         # poll bit must not be set
-        self.assertNotIn("P", p.sprintf("%BFD.flags%"),
-                         "Poll bit not set in BFD packet")
+        self.assertNotIn(
+            "P", p.sprintf("%BFD.flags%"), "Poll bit not set in BFD packet"
+        )
         self.vpp_session.modify_parameters(detect_mult=10)
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
-        self.assert_equal(self.vpp_session.detect_mult,
-                          p[BFD].detect_mult,
-                          "detect mult")
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
+        self.assert_equal(
+            self.vpp_session.detect_mult, p[BFD].detect_mult, "detect mult"
+        )
         # poll bit must not be set
-        self.assertNotIn("P", p.sprintf("%BFD.flags%"),
-                         "Poll bit not set in BFD packet")
+        self.assertNotIn(
+            "P", p.sprintf("%BFD.flags%"), "Poll bit not set in BFD packet"
+        )
 
     def test_queued_poll(self):
-        """ test poll sequence queueing """
+        """test poll sequence queueing"""
         bfd_session_up(self)
         p = wait_for_bfd_packet(self)
         self.vpp_session.modify_parameters(
-            required_min_rx=2 * self.vpp_session.required_min_rx)
+            required_min_rx=2 * self.vpp_session.required_min_rx
+        )
         p = wait_for_bfd_packet(self)
         poll_sequence_start = time.time()
         poll_sequence_length_min = 0.5
         send_final_after = time.time() + poll_sequence_length_min
         # poll bit needs to be set
-        self.assertIn("P", p.sprintf("%BFD.flags%"),
-                      "Poll bit not set in BFD packet")
-        self.assert_equal(p[BFD].required_min_rx_interval,
-                          self.vpp_session.required_min_rx,
-                          "BFD required min rx interval")
+        self.assertIn("P", p.sprintf("%BFD.flags%"), "Poll bit not set in BFD packet")
+        self.assert_equal(
+            p[BFD].required_min_rx_interval,
+            self.vpp_session.required_min_rx,
+            "BFD required min rx interval",
+        )
         self.vpp_session.modify_parameters(
-            required_min_rx=2 * self.vpp_session.required_min_rx)
+            required_min_rx=2 * self.vpp_session.required_min_rx
+        )
         # 2nd poll sequence should be queued now
         # don't send the reply back yet, wait for some time to emulate
         # longer round-trip time
@@ -1082,15 +1174,19 @@ class BFD4TestCase(VppTestCase):
         while time.time() < send_final_after:
             self.test_session.send_packet()
             p = wait_for_bfd_packet(self)
-            self.assert_equal(len(self.vapi.collect_events()), 0,
-                              "number of bfd events")
-            self.assert_equal(p[BFD].required_min_rx_interval,
-                              self.vpp_session.required_min_rx,
-                              "BFD required min rx interval")
+            self.assert_equal(
+                len(self.vapi.collect_events()), 0, "number of bfd events"
+            )
+            self.assert_equal(
+                p[BFD].required_min_rx_interval,
+                self.vpp_session.required_min_rx,
+                "BFD required min rx interval",
+            )
             packet_count += 1
             # poll bit must be set
-            self.assertIn("P", p.sprintf("%BFD.flags%"),
-                          "Poll bit not set in BFD packet")
+            self.assertIn(
+                "P", p.sprintf("%BFD.flags%"), "Poll bit not set in BFD packet"
+            )
         final = self.test_session.create_packet()
         final[BFD].flags = "F"
         self.test_session.send_packet(final)
@@ -1100,8 +1196,9 @@ class BFD4TestCase(VppTestCase):
         poll_no_2_started = False
         for dummy in range(2 * packet_count):
             p = wait_for_bfd_packet(self)
-            self.assert_equal(len(self.vapi.collect_events()), 0,
-                              "number of bfd events")
+            self.assert_equal(
+                len(self.vapi.collect_events()), 0, "number of bfd events"
+            )
             if "P" in p.sprintf("%BFD.flags%"):
                 poll_no_2_started = True
                 if time.time() < poll_sequence_start + poll_sequence_length:
@@ -1119,31 +1216,32 @@ class BFD4TestCase(VppTestCase):
         self.test_session.send_packet(final)
         p = wait_for_bfd_packet(self)
         # poll bit must not be set
-        self.assertNotIn("P", p.sprintf("%BFD.flags%"),
-                         "Poll bit set in BFD packet")
+        self.assertNotIn("P", p.sprintf("%BFD.flags%"), "Poll bit set in BFD packet")
 
     # returning inconsistent results requiring retries in per-patch tests
     @unittest.skipUnless(config.extended, "part of extended tests")
     def test_poll_response(self):
-        """ test correct response to control frame with poll bit set """
+        """test correct response to control frame with poll bit set"""
         bfd_session_up(self)
         poll = self.test_session.create_packet()
         poll[BFD].flags = "P"
         self.test_session.send_packet(poll)
         final = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
+            self, pcap_time_min=time.time() - self.vpp_clock_offset
+        )
         self.assertIn("F", final.sprintf("%BFD.flags%"))
 
     def test_no_periodic_if_remote_demand(self):
-        """ no periodic frames outside poll sequence if remote demand set """
+        """no periodic frames outside poll sequence if remote demand set"""
         bfd_session_up(self)
         demand = self.test_session.create_packet()
         demand[BFD].flags = "D"
         self.test_session.send_packet(demand)
-        transmit_time = 0.9 \
-            * max(self.vpp_session.required_min_rx,
-                  self.test_session.desired_min_tx) \
+        transmit_time = (
+            0.9
+            * max(self.vpp_session.required_min_rx, self.test_session.desired_min_tx)
             / USEC_IN_SEC
+        )
         count = 0
         for dummy in range(self.test_session.detect_mult * 2):
             self.sleep(transmit_time)
@@ -1161,7 +1259,7 @@ class BFD4TestCase(VppTestCase):
         self.assert_equal(len(events), 0, "number of events received")
 
     def test_echo_looped_back(self):
-        """ echo packets looped back """
+        """echo packets looped back"""
         bfd_session_up(self)
         stats_before = bfd_grab_stats_snapshot(self)
         self.pg0.enable_capture()
@@ -1169,14 +1267,14 @@ class BFD4TestCase(VppTestCase):
         # random source port low enough to increment a few times..
         udp_sport_tx = randint(1, 50000)
         udp_sport_rx = udp_sport_tx
-        echo_packet = (Ether(src=self.pg0.remote_mac,
-                             dst=self.pg0.local_mac) /
-                       IP(src=self.pg0.remote_ip4,
-                          dst=self.pg0.remote_ip4) /
-                       UDP(dport=BFD.udp_dport_echo) /
-                       Raw("this should be looped back"))
+        echo_packet = (
+            Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
+            / IP(src=self.pg0.remote_ip4, dst=self.pg0.remote_ip4)
+            / UDP(dport=BFD.udp_dport_echo)
+            / Raw("this should be looped back")
+        )
         for dummy in range(echo_packet_count):
-            self.sleep(.01, "delay between echo packets")
+            self.sleep(0.01, "delay between echo packets")
             echo_packet[UDP].sport = udp_sport_tx
             udp_sport_tx += 1
             self.logger.debug(ppp("Sending packet:", echo_packet))
@@ -1189,8 +1287,7 @@ class BFD4TestCase(VppTestCase):
             p = self.pg0.wait_for_packet(1)
             self.logger.debug(ppp("Got packet:", p))
             ether = p[Ether]
-            self.assert_equal(self.pg0.remote_mac,
-                              ether.dst, "Destination MAC")
+            self.assert_equal(self.pg0.remote_mac, ether.dst, "Destination MAC")
             self.assert_equal(self.pg0.local_mac, ether.src, "Source MAC")
             ip = p[IP]
             self.assert_equal(self.pg0.remote_ip4, ip.dst, "Destination IP")
@@ -1199,50 +1296,57 @@ class BFD4TestCase(VppTestCase):
                 bfd_control_packets_rx += 1
                 continue
             self.assert_equal(self.pg0.remote_ip4, ip.src, "Source IP")
-            self.assert_equal(udp.dport, BFD.udp_dport_echo,
-                              "UDP destination port")
+            self.assert_equal(udp.dport, BFD.udp_dport_echo, "UDP destination port")
             self.assert_equal(udp.sport, udp_sport_rx, "UDP source port")
             udp_sport_rx += 1
             # need to compare the hex payload here, otherwise BFD_vpp_echo
             # gets in way
-            self.assertEqual(scapy.compat.raw(p[UDP].payload),
-                             scapy.compat.raw(echo_packet[UDP].payload),
-                             "Received packet is not the echo packet sent")
+            self.assertEqual(
+                scapy.compat.raw(p[UDP].payload),
+                scapy.compat.raw(echo_packet[UDP].payload),
+                "Received packet is not the echo packet sent",
+            )
             counter += 1
-        self.assert_equal(udp_sport_tx, udp_sport_rx, "UDP source port (== "
-                          "ECHO packet identifier for test purposes)")
+        self.assert_equal(
+            udp_sport_tx,
+            udp_sport_rx,
+            "UDP source port (== ECHO packet identifier for test purposes)",
+        )
         stats_after = bfd_grab_stats_snapshot(self)
         diff = bfd_stats_diff(stats_before, stats_after)
+        self.assertEqual(0, diff.rx, "RX counter bumped but no BFD packets sent")
+        self.assertEqual(bfd_control_packets_rx, diff.tx, "TX counter incorrect")
         self.assertEqual(
-            0, diff.rx, "RX counter bumped but no BFD packets sent")
+            0, diff.rx_echo, "RX echo counter bumped but no BFD session exists"
+        )
         self.assertEqual(
-            bfd_control_packets_rx, diff.tx, "TX counter incorrect")
-        self.assertEqual(0, diff.rx_echo,
-                         "RX echo counter bumped but no BFD session exists")
-        self.assertEqual(0, diff.tx_echo,
-                         "TX echo counter bumped but no BFD session exists")
+            0, diff.tx_echo, "TX echo counter bumped but no BFD session exists"
+        )
 
     def test_echo(self):
-        """ echo function """
+        """echo function"""
         stats_before = bfd_grab_stats_snapshot(self)
         bfd_session_up(self)
         self.test_session.update(required_min_echo_rx=150000)
         self.test_session.send_packet()
-        detection_time = self.test_session.detect_mult *\
-            self.vpp_session.required_min_rx / USEC_IN_SEC
+        detection_time = (
+            self.test_session.detect_mult
+            * self.vpp_session.required_min_rx
+            / USEC_IN_SEC
+        )
         # echo shouldn't work without echo source set
         for dummy in range(10):
             sleep = self.vpp_session.required_min_rx / USEC_IN_SEC
             self.sleep(sleep, "delay before sending bfd packet")
             self.test_session.send_packet()
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
-        self.assert_equal(p[BFD].required_min_rx_interval,
-                          self.vpp_session.required_min_rx,
-                          "BFD required min rx interval")
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
+        self.assert_equal(
+            p[BFD].required_min_rx_interval,
+            self.vpp_session.required_min_rx,
+            "BFD required min rx interval",
+        )
         self.test_session.send_packet()
-        self.vapi.bfd_udp_set_echo_source(
-            sw_if_index=self.loopback0.sw_if_index)
+        self.vapi.bfd_udp_set_echo_source(sw_if_index=self.loopback0.sw_if_index)
         echo_seen = False
         # should be turned on - loopback echo packets
         for dummy in range(3):
@@ -1251,13 +1355,18 @@ class BFD4TestCase(VppTestCase):
                 p = self.pg0.wait_for_packet(1)
                 self.logger.debug(ppp("Got packet:", p))
                 if p[UDP].dport == BFD.udp_dport_echo:
-                    self.assert_equal(
-                        p[IP].dst, self.pg0.local_ip4, "BFD ECHO dst IP")
-                    self.assertNotEqual(p[IP].src, self.loopback0.local_ip4,
-                                        "BFD ECHO src IP equal to loopback IP")
+                    self.assert_equal(p[IP].dst, self.pg0.local_ip4, "BFD ECHO dst IP")
+                    self.assertNotEqual(
+                        p[IP].src,
+                        self.loopback0.local_ip4,
+                        "BFD ECHO src IP equal to loopback IP",
+                    )
                     self.logger.debug(ppp("Looping back packet:", p))
-                    self.assert_equal(p[Ether].dst, self.pg0.remote_mac,
-                                      "ECHO packet destination MAC address")
+                    self.assert_equal(
+                        p[Ether].dst,
+                        self.pg0.remote_mac,
+                        "ECHO packet destination MAC address",
+                    )
                     p[Ether].dst = self.pg0.local_mac
                     self.pg0.add_stream(p)
                     self.test_session.rx_packets_echo += 1
@@ -1268,8 +1377,8 @@ class BFD4TestCase(VppTestCase):
                     self.test_session.rx_packets += 1
                     if echo_seen:
                         self.assertGreaterEqual(
-                            p[BFD].required_min_rx_interval,
-                            1000000)
+                            p[BFD].required_min_rx_interval, 1000000
+                        )
                     if "P" in p.sprintf("%BFD.flags%"):
                         final = self.test_session.create_packet()
                         final[BFD].flags = "F"
@@ -1277,34 +1386,45 @@ class BFD4TestCase(VppTestCase):
                 else:
                     raise Exception(ppp("Received unknown packet:", p))
 
-                self.assert_equal(len(self.vapi.collect_events()), 0,
-                                  "number of bfd events")
+                self.assert_equal(
+                    len(self.vapi.collect_events()), 0, "number of bfd events"
+                )
             self.test_session.send_packet()
         self.assertTrue(echo_seen, "No echo packets received")
 
         stats_after = bfd_grab_stats_snapshot(self)
         diff = bfd_stats_diff(stats_before, stats_after)
         # our rx is vpp tx and vice versa, also tolerate one packet off
-        self.assert_in_range(self.test_session.tx_packets,
-                             diff.rx - 1, diff.rx + 1, "RX counter")
-        self.assert_in_range(self.test_session.rx_packets,
-                             diff.tx - 1, diff.tx + 1, "TX counter")
-        self.assert_in_range(self.test_session.tx_packets_echo,
-                             diff.rx_echo - 1, diff.rx_echo + 1,
-                             "RX echo counter")
-        self.assert_in_range(self.test_session.rx_packets_echo,
-                             diff.tx_echo - 1, diff.tx_echo + 1,
-                             "TX echo counter")
+        self.assert_in_range(
+            self.test_session.tx_packets, diff.rx - 1, diff.rx + 1, "RX counter"
+        )
+        self.assert_in_range(
+            self.test_session.rx_packets, diff.tx - 1, diff.tx + 1, "TX counter"
+        )
+        self.assert_in_range(
+            self.test_session.tx_packets_echo,
+            diff.rx_echo - 1,
+            diff.rx_echo + 1,
+            "RX echo counter",
+        )
+        self.assert_in_range(
+            self.test_session.rx_packets_echo,
+            diff.tx_echo - 1,
+            diff.tx_echo + 1,
+            "TX echo counter",
+        )
 
     def test_echo_fail(self):
-        """ session goes down if echo function fails """
+        """session goes down if echo function fails"""
         bfd_session_up(self)
         self.test_session.update(required_min_echo_rx=150000)
         self.test_session.send_packet()
-        detection_time = self.test_session.detect_mult *\
-            self.vpp_session.required_min_rx / USEC_IN_SEC
-        self.vapi.bfd_udp_set_echo_source(
-            sw_if_index=self.loopback0.sw_if_index)
+        detection_time = (
+            self.test_session.detect_mult
+            * self.vpp_session.required_min_rx
+            / USEC_IN_SEC
+        )
+        self.vapi.bfd_udp_set_echo_source(sw_if_index=self.loopback0.sw_if_index)
         # echo function should be used now, but we will drop the echo packets
         verified_diag = False
         for dummy in range(3):
@@ -1318,15 +1438,15 @@ class BFD4TestCase(VppTestCase):
                 elif p.haslayer(BFD):
                     if "P" in p.sprintf("%BFD.flags%"):
                         self.assertGreaterEqual(
-                            p[BFD].required_min_rx_interval,
-                            1000000)
+                            p[BFD].required_min_rx_interval, 1000000
+                        )
                         final = self.test_session.create_packet()
                         final[BFD].flags = "F"
                         self.test_session.send_packet(final)
                     if p[BFD].state == BFDState.down:
-                        self.assert_equal(p[BFD].diag,
-                                          BFDDiagCode.echo_function_failed,
-                                          BFDDiagCode)
+                        self.assert_equal(
+                            p[BFD].diag, BFDDiagCode.echo_function_failed, BFDDiagCode
+                        )
                         verified_diag = True
                 else:
                     raise Exception(ppp("Received unknown packet:", p))
@@ -1337,12 +1457,11 @@ class BFD4TestCase(VppTestCase):
         self.assertTrue(verified_diag, "Incorrect diagnostics code received")
 
     def test_echo_stop(self):
-        """ echo function stops if peer sets required min echo rx zero """
+        """echo function stops if peer sets required min echo rx zero"""
         bfd_session_up(self)
         self.test_session.update(required_min_echo_rx=150000)
         self.test_session.send_packet()
-        self.vapi.bfd_udp_set_echo_source(
-            sw_if_index=self.loopback0.sw_if_index)
+        self.vapi.bfd_udp_set_echo_source(sw_if_index=self.loopback0.sw_if_index)
         # wait for first echo packet
         while True:
             p = self.pg0.wait_for_packet(1)
@@ -1362,19 +1481,17 @@ class BFD4TestCase(VppTestCase):
         self.test_session.send_packet()
         # echo packets shouldn't arrive anymore
         for dummy in range(5):
-            wait_for_bfd_packet(
-                self, pcap_time_min=time.time() - self.vpp_clock_offset)
+            wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
             self.test_session.send_packet()
             events = self.vapi.collect_events()
             self.assert_equal(len(events), 0, "number of bfd events")
 
     def test_echo_source_removed(self):
-        """ echo function stops if echo source is removed """
+        """echo function stops if echo source is removed"""
         bfd_session_up(self)
         self.test_session.update(required_min_echo_rx=150000)
         self.test_session.send_packet()
-        self.vapi.bfd_udp_set_echo_source(
-            sw_if_index=self.loopback0.sw_if_index)
+        self.vapi.bfd_udp_set_echo_source(sw_if_index=self.loopback0.sw_if_index)
         # wait for first echo packet
         while True:
             p = self.pg0.wait_for_packet(1)
@@ -1394,18 +1511,16 @@ class BFD4TestCase(VppTestCase):
         self.test_session.send_packet()
         # echo packets shouldn't arrive anymore
         for dummy in range(5):
-            wait_for_bfd_packet(
-                self, pcap_time_min=time.time() - self.vpp_clock_offset)
+            wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
             self.test_session.send_packet()
             events = self.vapi.collect_events()
             self.assert_equal(len(events), 0, "number of bfd events")
 
     def test_stale_echo(self):
-        """ stale echo packets don't keep a session up """
+        """stale echo packets don't keep a session up"""
         bfd_session_up(self)
         self.test_session.update(required_min_echo_rx=150000)
-        self.vapi.bfd_udp_set_echo_source(
-            sw_if_index=self.loopback0.sw_if_index)
+        self.vapi.bfd_udp_set_echo_source(sw_if_index=self.loopback0.sw_if_index)
         self.test_session.send_packet()
         # should be turned on - loopback echo packets
         echo_packet = None
@@ -1417,8 +1532,12 @@ class BFD4TestCase(VppTestCase):
                 if echo_packet is None:
                     self.logger.debug(ppp("Got first echo packet:", p))
                     echo_packet = p
-                    timeout_at = time.time() + self.vpp_session.detect_mult * \
-                        self.test_session.required_min_echo_rx / USEC_IN_SEC
+                    timeout_at = (
+                        time.time()
+                        + self.vpp_session.detect_mult
+                        * self.test_session.required_min_echo_rx
+                        / USEC_IN_SEC
+                    )
                 else:
                     self.logger.debug(ppp("Got followup echo packet:", p))
                 self.logger.debug(ppp("Looping back first echo packet:", p))
@@ -1434,15 +1553,18 @@ class BFD4TestCase(VppTestCase):
                 if p[BFD].state == BFDState.down:
                     self.assertIsNotNone(
                         timeout_at,
-                        "Session went down before first echo packet received")
+                        "Session went down before first echo packet received",
+                    )
                     now = time.time()
                     self.assertGreaterEqual(
-                        now, timeout_at,
-                        "Session timeout at %s, but is expected at %s" %
-                        (now, timeout_at))
-                    self.assert_equal(p[BFD].diag,
-                                      BFDDiagCode.echo_function_failed,
-                                      BFDDiagCode)
+                        now,
+                        timeout_at,
+                        "Session timeout at %s, but is expected at %s"
+                        % (now, timeout_at),
+                    )
+                    self.assert_equal(
+                        p[BFD].diag, BFDDiagCode.echo_function_failed, BFDDiagCode
+                    )
                     events = self.vapi.collect_events()
                     self.assert_equal(len(events), 1, "number of bfd events")
                     self.assert_equal(events[0].state, BFDState.down, BFDState)
@@ -1454,11 +1576,10 @@ class BFD4TestCase(VppTestCase):
         self.assertTrue(timeout_ok, "Expected timeout event didn't occur")
 
     def test_invalid_echo_checksum(self):
-        """ echo packets with invalid checksum don't keep a session up """
+        """echo packets with invalid checksum don't keep a session up"""
         bfd_session_up(self)
         self.test_session.update(required_min_echo_rx=150000)
-        self.vapi.bfd_udp_set_echo_source(
-            sw_if_index=self.loopback0.sw_if_index)
+        self.vapi.bfd_udp_set_echo_source(sw_if_index=self.loopback0.sw_if_index)
         self.test_session.send_packet()
         # should be turned on - loopback echo packets
         timeout_at = None
@@ -1468,8 +1589,12 @@ class BFD4TestCase(VppTestCase):
             if p[UDP].dport == BFD.udp_dport_echo:
                 self.logger.debug(ppp("Got echo packet:", p))
                 if timeout_at is None:
-                    timeout_at = time.time() + self.vpp_session.detect_mult * \
-                        self.test_session.required_min_echo_rx / USEC_IN_SEC
+                    timeout_at = (
+                        time.time()
+                        + self.vpp_session.detect_mult
+                        * self.test_session.required_min_echo_rx
+                        / USEC_IN_SEC
+                    )
                 p[BFD_vpp_echo].checksum = getrandbits(64)
                 p[Ether].dst = self.pg0.local_mac
                 self.logger.debug(ppp("Looping back modified echo packet:", p))
@@ -1484,15 +1609,18 @@ class BFD4TestCase(VppTestCase):
                 if p[BFD].state == BFDState.down:
                     self.assertIsNotNone(
                         timeout_at,
-                        "Session went down before first echo packet received")
+                        "Session went down before first echo packet received",
+                    )
                     now = time.time()
                     self.assertGreaterEqual(
-                        now, timeout_at,
-                        "Session timeout at %s, but is expected at %s" %
-                        (now, timeout_at))
-                    self.assert_equal(p[BFD].diag,
-                                      BFDDiagCode.echo_function_failed,
-                                      BFDDiagCode)
+                        now,
+                        timeout_at,
+                        "Session timeout at %s, but is expected at %s"
+                        % (now, timeout_at),
+                    )
+                    self.assert_equal(
+                        p[BFD].diag, BFDDiagCode.echo_function_failed, BFDDiagCode
+                    )
                     events = self.vapi.collect_events()
                     self.assert_equal(len(events), 1, "number of bfd events")
                     self.assert_equal(events[0].state, BFDState.down, BFDState)
@@ -1504,7 +1632,7 @@ class BFD4TestCase(VppTestCase):
         self.assertTrue(timeout_ok, "Expected timeout event didn't occur")
 
     def test_admin_up_down(self):
-        """ put session admin-up and admin-down """
+        """put session admin-up and admin-down"""
         bfd_session_up(self)
         self.vpp_session.admin_down()
         self.pg0.enable_capture()
@@ -1523,33 +1651,30 @@ class BFD4TestCase(VppTestCase):
         self.test_session.update(state=BFDState.down)
         e = self.vapi.wait_for_event(1, "bfd_udp_session_event")
         verify_event(self, e, expected_state=BFDState.down)
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
         self.assert_equal(p[BFD].state, BFDState.down, BFDState)
         self.test_session.send_packet()
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
         self.assert_equal(p[BFD].state, BFDState.init, BFDState)
         e = self.vapi.wait_for_event(1, "bfd_udp_session_event")
         verify_event(self, e, expected_state=BFDState.init)
         self.test_session.update(state=BFDState.up)
         self.test_session.send_packet()
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
         self.assert_equal(p[BFD].state, BFDState.up, BFDState)
         e = self.vapi.wait_for_event(1, "bfd_udp_session_event")
         verify_event(self, e, expected_state=BFDState.up)
 
     def test_config_change_remote_demand(self):
-        """ configuration change while peer in demand mode """
+        """configuration change while peer in demand mode"""
         bfd_session_up(self)
         demand = self.test_session.create_packet()
         demand[BFD].flags = "D"
         self.test_session.send_packet(demand)
         self.vpp_session.modify_parameters(
-            required_min_rx=2 * self.vpp_session.required_min_rx)
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
+            required_min_rx=2 * self.vpp_session.required_min_rx
+        )
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
         # poll bit must be set
         self.assertIn("P", p.sprintf("%BFD.flags%"), "Poll bit not set")
         # terminate poll sequence
@@ -1557,10 +1682,11 @@ class BFD4TestCase(VppTestCase):
         final[BFD].flags = "D+F"
         self.test_session.send_packet(final)
         # vpp should be quiet now again
-        transmit_time = 0.9 \
-            * max(self.vpp_session.required_min_rx,
-                  self.test_session.desired_min_tx) \
+        transmit_time = (
+            0.9
+            * max(self.vpp_session.required_min_rx, self.test_session.desired_min_tx)
             / USEC_IN_SEC
+        )
         count = 0
         for dummy in range(self.test_session.detect_mult * 2):
             self.sleep(transmit_time)
@@ -1578,7 +1704,7 @@ class BFD4TestCase(VppTestCase):
         self.assert_equal(len(events), 0, "number of events received")
 
     def test_intf_deleted(self):
-        """ interface with bfd session deleted """
+        """interface with bfd session deleted"""
         intf = VppLoInterface(self)
         intf.config_ip4()
         intf.admin_up()
@@ -1595,7 +1721,7 @@ class BFD4TestCase(VppTestCase):
 @tag_run_solo
 @tag_fixme_vpp_workers
 class BFD6TestCase(VppTestCase):
-    """Bidirectional Forwarding Detection (BFD) (IPv6) """
+    """Bidirectional Forwarding Detection (BFD) (IPv6)"""
 
     pg0 = None
     vpp_clock_offset = None
@@ -1631,11 +1757,11 @@ class BFD6TestCase(VppTestCase):
         self.vapi.want_bfd_events()
         self.pg0.enable_capture()
         try:
-            self.bfd_udp4_sessions = self.statistics['/bfd/udp4/sessions']
-            self.bfd_udp6_sessions = self.statistics['/bfd/udp6/sessions']
-            self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                                self.pg0.remote_ip6,
-                                                af=AF_INET6)
+            self.bfd_udp4_sessions = self.statistics["/bfd/udp4/sessions"]
+            self.bfd_udp6_sessions = self.statistics["/bfd/udp6/sessions"]
+            self.vpp_session = VppBFDUDPSession(
+                self, self.pg0, self.pg0.remote_ip6, af=AF_INET6
+            )
             self.vpp_session.add_vpp_config()
             self.vpp_session.admin_up()
             self.test_session = BFDTestSession(self, self.pg0, AF_INET6)
@@ -1651,26 +1777,29 @@ class BFD6TestCase(VppTestCase):
         super(BFD6TestCase, self).tearDown()
 
     def test_session_up(self):
-        """ bring BFD session up """
+        """bring BFD session up"""
         bfd_session_up(self)
-        bfd_udp4_sessions = self.statistics['/bfd/udp4/sessions']
-        bfd_udp6_sessions = self.statistics['/bfd/udp6/sessions']
+        bfd_udp4_sessions = self.statistics["/bfd/udp4/sessions"]
+        bfd_udp6_sessions = self.statistics["/bfd/udp6/sessions"]
         self.assert_equal(bfd_udp4_sessions, self.bfd_udp4_sessions)
         self.assert_equal(bfd_udp6_sessions - self.bfd_udp6_sessions, 1)
 
     def test_session_up_by_ip(self):
-        """ bring BFD session up - first frame looked up by address pair """
+        """bring BFD session up - first frame looked up by address pair"""
         self.logger.info("BFD: Sending Slow control frame")
         self.test_session.update(my_discriminator=randint(0, 40000000))
         self.test_session.send_packet()
         self.pg0.enable_capture()
         p = self.pg0.wait_for_packet(1)
-        self.assert_equal(p[BFD].your_discriminator,
-                          self.test_session.my_discriminator,
-                          "BFD - your discriminator")
+        self.assert_equal(
+            p[BFD].your_discriminator,
+            self.test_session.my_discriminator,
+            "BFD - your discriminator",
+        )
         self.assert_equal(p[BFD].state, BFDState.init, BFDState)
-        self.test_session.update(your_discriminator=p[BFD].my_discriminator,
-                                 state=BFDState.up)
+        self.test_session.update(
+            your_discriminator=p[BFD].my_discriminator, state=BFDState.up
+        )
         self.logger.info("BFD: Waiting for event")
         e = self.vapi.wait_for_event(1, "bfd_udp_session_event")
         verify_event(self, e, expected_state=BFDState.init)
@@ -1685,17 +1814,16 @@ class BFD6TestCase(VppTestCase):
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
 
     def test_hold_up(self):
-        """ hold BFD session up """
+        """hold BFD session up"""
         bfd_session_up(self)
         for dummy in range(self.test_session.detect_mult * 2):
             wait_for_bfd_packet(self)
             self.test_session.send_packet()
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
 
     def test_echo_looped_back(self):
-        """ echo packets looped back """
+        """echo packets looped back"""
         bfd_session_up(self)
         stats_before = bfd_grab_stats_snapshot(self)
         self.pg0.enable_capture()
@@ -1703,14 +1831,14 @@ class BFD6TestCase(VppTestCase):
         # random source port low enough to increment a few times..
         udp_sport_tx = randint(1, 50000)
         udp_sport_rx = udp_sport_tx
-        echo_packet = (Ether(src=self.pg0.remote_mac,
-                             dst=self.pg0.local_mac) /
-                       IPv6(src=self.pg0.remote_ip6,
-                            dst=self.pg0.remote_ip6) /
-                       UDP(dport=BFD.udp_dport_echo) /
-                       Raw("this should be looped back"))
+        echo_packet = (
+            Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
+            / IPv6(src=self.pg0.remote_ip6, dst=self.pg0.remote_ip6)
+            / UDP(dport=BFD.udp_dport_echo)
+            / Raw("this should be looped back")
+        )
         for dummy in range(echo_packet_count):
-            self.sleep(.01, "delay between echo packets")
+            self.sleep(0.01, "delay between echo packets")
             echo_packet[UDP].sport = udp_sport_tx
             udp_sport_tx += 1
             self.logger.debug(ppp("Sending packet:", echo_packet))
@@ -1722,8 +1850,7 @@ class BFD6TestCase(VppTestCase):
             p = self.pg0.wait_for_packet(1)
             self.logger.debug(ppp("Got packet:", p))
             ether = p[Ether]
-            self.assert_equal(self.pg0.remote_mac,
-                              ether.dst, "Destination MAC")
+            self.assert_equal(self.pg0.remote_mac, ether.dst, "Destination MAC")
             self.assert_equal(self.pg0.local_mac, ether.src, "Source MAC")
             ip = p[IPv6]
             self.assert_equal(self.pg0.remote_ip6, ip.dst, "Destination IP")
@@ -1732,50 +1859,57 @@ class BFD6TestCase(VppTestCase):
                 bfd_control_packets_rx += 1
                 continue
             self.assert_equal(self.pg0.remote_ip6, ip.src, "Source IP")
-            self.assert_equal(udp.dport, BFD.udp_dport_echo,
-                              "UDP destination port")
+            self.assert_equal(udp.dport, BFD.udp_dport_echo, "UDP destination port")
             self.assert_equal(udp.sport, udp_sport_rx, "UDP source port")
             udp_sport_rx += 1
             # need to compare the hex payload here, otherwise BFD_vpp_echo
             # gets in way
-            self.assertEqual(scapy.compat.raw(p[UDP].payload),
-                             scapy.compat.raw(echo_packet[UDP].payload),
-                             "Received packet is not the echo packet sent")
+            self.assertEqual(
+                scapy.compat.raw(p[UDP].payload),
+                scapy.compat.raw(echo_packet[UDP].payload),
+                "Received packet is not the echo packet sent",
+            )
             counter += 1
-        self.assert_equal(udp_sport_tx, udp_sport_rx, "UDP source port (== "
-                          "ECHO packet identifier for test purposes)")
+        self.assert_equal(
+            udp_sport_tx,
+            udp_sport_rx,
+            "UDP source port (== ECHO packet identifier for test purposes)",
+        )
         stats_after = bfd_grab_stats_snapshot(self)
         diff = bfd_stats_diff(stats_before, stats_after)
+        self.assertEqual(0, diff.rx, "RX counter bumped but no BFD packets sent")
+        self.assertEqual(bfd_control_packets_rx, diff.tx, "TX counter incorrect")
         self.assertEqual(
-            0, diff.rx, "RX counter bumped but no BFD packets sent")
-        self.assertEqual(bfd_control_packets_rx,
-                         diff.tx, "TX counter incorrect")
-        self.assertEqual(0, diff.rx_echo,
-                         "RX echo counter bumped but no BFD session exists")
-        self.assertEqual(0, diff.tx_echo,
-                         "TX echo counter bumped but no BFD session exists")
+            0, diff.rx_echo, "RX echo counter bumped but no BFD session exists"
+        )
+        self.assertEqual(
+            0, diff.tx_echo, "TX echo counter bumped but no BFD session exists"
+        )
 
     def test_echo(self):
-        """ echo function """
+        """echo function"""
         stats_before = bfd_grab_stats_snapshot(self)
         bfd_session_up(self)
         self.test_session.update(required_min_echo_rx=150000)
         self.test_session.send_packet()
-        detection_time = self.test_session.detect_mult *\
-            self.vpp_session.required_min_rx / USEC_IN_SEC
+        detection_time = (
+            self.test_session.detect_mult
+            * self.vpp_session.required_min_rx
+            / USEC_IN_SEC
+        )
         # echo shouldn't work without echo source set
         for dummy in range(10):
             sleep = self.vpp_session.required_min_rx / USEC_IN_SEC
             self.sleep(sleep, "delay before sending bfd packet")
             self.test_session.send_packet()
-        p = wait_for_bfd_packet(
-            self, pcap_time_min=time.time() - self.vpp_clock_offset)
-        self.assert_equal(p[BFD].required_min_rx_interval,
-                          self.vpp_session.required_min_rx,
-                          "BFD required min rx interval")
+        p = wait_for_bfd_packet(self, pcap_time_min=time.time() - self.vpp_clock_offset)
+        self.assert_equal(
+            p[BFD].required_min_rx_interval,
+            self.vpp_session.required_min_rx,
+            "BFD required min rx interval",
+        )
         self.test_session.send_packet()
-        self.vapi.bfd_udp_set_echo_source(
-            sw_if_index=self.loopback0.sw_if_index)
+        self.vapi.bfd_udp_set_echo_source(sw_if_index=self.loopback0.sw_if_index)
         echo_seen = False
         # should be turned on - loopback echo packets
         for dummy in range(3):
@@ -1785,12 +1919,19 @@ class BFD6TestCase(VppTestCase):
                 self.logger.debug(ppp("Got packet:", p))
                 if p[UDP].dport == BFD.udp_dport_echo:
                     self.assert_equal(
-                        p[IPv6].dst, self.pg0.local_ip6, "BFD ECHO dst IP")
-                    self.assertNotEqual(p[IPv6].src, self.loopback0.local_ip6,
-                                        "BFD ECHO src IP equal to loopback IP")
+                        p[IPv6].dst, self.pg0.local_ip6, "BFD ECHO dst IP"
+                    )
+                    self.assertNotEqual(
+                        p[IPv6].src,
+                        self.loopback0.local_ip6,
+                        "BFD ECHO src IP equal to loopback IP",
+                    )
                     self.logger.debug(ppp("Looping back packet:", p))
-                    self.assert_equal(p[Ether].dst, self.pg0.remote_mac,
-                                      "ECHO packet destination MAC address")
+                    self.assert_equal(
+                        p[Ether].dst,
+                        self.pg0.remote_mac,
+                        "ECHO packet destination MAC address",
+                    )
                     self.test_session.rx_packets_echo += 1
                     self.test_session.tx_packets_echo += 1
                     p[Ether].dst = self.pg0.local_mac
@@ -1801,8 +1942,8 @@ class BFD6TestCase(VppTestCase):
                     self.test_session.rx_packets += 1
                     if echo_seen:
                         self.assertGreaterEqual(
-                            p[BFD].required_min_rx_interval,
-                            1000000)
+                            p[BFD].required_min_rx_interval, 1000000
+                        )
                     if "P" in p.sprintf("%BFD.flags%"):
                         final = self.test_session.create_packet()
                         final[BFD].flags = "F"
@@ -1810,33 +1951,41 @@ class BFD6TestCase(VppTestCase):
                 else:
                     raise Exception(ppp("Received unknown packet:", p))
 
-                self.assert_equal(len(self.vapi.collect_events()), 0,
-                                  "number of bfd events")
+                self.assert_equal(
+                    len(self.vapi.collect_events()), 0, "number of bfd events"
+                )
             self.test_session.send_packet()
         self.assertTrue(echo_seen, "No echo packets received")
 
         stats_after = bfd_grab_stats_snapshot(self)
         diff = bfd_stats_diff(stats_before, stats_after)
         # our rx is vpp tx and vice versa, also tolerate one packet off
-        self.assert_in_range(self.test_session.tx_packets,
-                             diff.rx - 1, diff.rx + 1, "RX counter")
-        self.assert_in_range(self.test_session.rx_packets,
-                             diff.tx - 1, diff.tx + 1, "TX counter")
-        self.assert_in_range(self.test_session.tx_packets_echo,
-                             diff.rx_echo - 1, diff.rx_echo + 1,
-                             "RX echo counter")
-        self.assert_in_range(self.test_session.rx_packets_echo,
-                             diff.tx_echo - 1, diff.tx_echo + 1,
-                             "TX echo counter")
+        self.assert_in_range(
+            self.test_session.tx_packets, diff.rx - 1, diff.rx + 1, "RX counter"
+        )
+        self.assert_in_range(
+            self.test_session.rx_packets, diff.tx - 1, diff.tx + 1, "TX counter"
+        )
+        self.assert_in_range(
+            self.test_session.tx_packets_echo,
+            diff.rx_echo - 1,
+            diff.rx_echo + 1,
+            "RX echo counter",
+        )
+        self.assert_in_range(
+            self.test_session.rx_packets_echo,
+            diff.tx_echo - 1,
+            diff.tx_echo + 1,
+            "TX echo counter",
+        )
 
     def test_intf_deleted(self):
-        """ interface with bfd session deleted """
+        """interface with bfd session deleted"""
         intf = VppLoInterface(self)
         intf.config_ip6()
         intf.admin_up()
         sw_if_index = intf.sw_if_index
-        vpp_session = VppBFDUDPSession(
-            self, intf, intf.remote_ip6, af=AF_INET6)
+        vpp_session = VppBFDUDPSession(self, intf, intf.remote_ip6, af=AF_INET6)
         vpp_session.add_vpp_config()
         vpp_session.admin_up()
         intf.remove_vpp_config()
@@ -1847,7 +1996,7 @@ class BFD6TestCase(VppTestCase):
 
 @tag_run_solo
 class BFDFIBTestCase(VppTestCase):
-    """ BFD-FIB interactions (IPv6) """
+    """BFD-FIB interactions (IPv6)"""
 
     vpp_session = None
     test_session = None
@@ -1880,40 +2029,48 @@ class BFDFIBTestCase(VppTestCase):
 
     @staticmethod
     def pkt_is_not_data_traffic(p):
-        """ not data traffic implies BFD or the usual IPv6 ND/RA"""
+        """not data traffic implies BFD or the usual IPv6 ND/RA"""
         if p.haslayer(BFD) or is_ipv6_misc(p):
             return True
         return False
 
     def test_session_with_fib(self):
-        """ BFD-FIB interactions """
+        """BFD-FIB interactions"""
 
         # packets to match against both of the routes
-        p = [(Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
-              IPv6(src="3001::1", dst="2001::1") /
-              UDP(sport=1234, dport=1234) /
-              Raw(b'\xa5' * 100)),
-             (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
-              IPv6(src="3001::1", dst="2002::1") /
-              UDP(sport=1234, dport=1234) /
-              Raw(b'\xa5' * 100))]
+        p = [
+            (
+                Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
+                / IPv6(src="3001::1", dst="2001::1")
+                / UDP(sport=1234, dport=1234)
+                / Raw(b"\xa5" * 100)
+            ),
+            (
+                Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
+                / IPv6(src="3001::1", dst="2002::1")
+                / UDP(sport=1234, dport=1234)
+                / Raw(b"\xa5" * 100)
+            ),
+        ]
 
         # A recursive and a non-recursive route via a next-hop that
         # will have a BFD session
-        ip_2001_s_64 = VppIpRoute(self, "2001::", 64,
-                                  [VppRoutePath(self.pg0.remote_ip6,
-                                                self.pg0.sw_if_index)])
-        ip_2002_s_64 = VppIpRoute(self, "2002::", 64,
-                                  [VppRoutePath(self.pg0.remote_ip6,
-                                                0xffffffff)])
+        ip_2001_s_64 = VppIpRoute(
+            self,
+            "2001::",
+            64,
+            [VppRoutePath(self.pg0.remote_ip6, self.pg0.sw_if_index)],
+        )
+        ip_2002_s_64 = VppIpRoute(
+            self, "2002::", 64, [VppRoutePath(self.pg0.remote_ip6, 0xFFFFFFFF)]
+        )
         ip_2001_s_64.add_vpp_config()
         ip_2002_s_64.add_vpp_config()
 
         # bring the session up now the routes are present
-        self.vpp_session = VppBFDUDPSession(self,
-                                            self.pg0,
-                                            self.pg0.remote_ip6,
-                                            af=AF_INET6)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6
+        )
         self.vpp_session.add_vpp_config()
         self.vpp_session.admin_up()
         self.test_session = BFDTestSession(self, self.pg0, AF_INET6)
@@ -1925,10 +2082,9 @@ class BFDFIBTestCase(VppTestCase):
         self.pg_start()
         for packet in p:
             captured = self.pg0.wait_for_packet(
-                1,
-                filter_out_fn=self.pkt_is_not_data_traffic)
-            self.assertEqual(captured[IPv6].dst,
-                             packet[IPv6].dst)
+                1, filter_out_fn=self.pkt_is_not_data_traffic
+            )
+            self.assertEqual(captured[IPv6].dst, packet[IPv6].dst)
 
         # session is up - traffic is dropped
         bfd_session_down(self)
@@ -1945,15 +2101,14 @@ class BFDFIBTestCase(VppTestCase):
         self.pg_start()
         for packet in p:
             captured = self.pg0.wait_for_packet(
-                1,
-                filter_out_fn=self.pkt_is_not_data_traffic)
-            self.assertEqual(captured[IPv6].dst,
-                             packet[IPv6].dst)
+                1, filter_out_fn=self.pkt_is_not_data_traffic
+            )
+            self.assertEqual(captured[IPv6].dst, packet[IPv6].dst)
 
 
 @unittest.skipUnless(config.extended, "part of extended tests")
 class BFDTunTestCase(VppTestCase):
-    """ BFD over GRE tunnel """
+    """BFD over GRE tunnel"""
 
     vpp_session = None
     test_session = None
@@ -1986,42 +2141,44 @@ class BFDTunTestCase(VppTestCase):
 
     @staticmethod
     def pkt_is_not_data_traffic(p):
-        """ not data traffic implies BFD or the usual IPv6 ND/RA"""
+        """not data traffic implies BFD or the usual IPv6 ND/RA"""
         if p.haslayer(BFD) or is_ipv6_misc(p):
             return True
         return False
 
     def test_bfd_o_gre(self):
-        """ BFD-o-GRE  """
+        """BFD-o-GRE"""
 
         # A GRE interface over which to run a BFD session
-        gre_if = VppGreInterface(self,
-                                 self.pg0.local_ip4,
-                                 self.pg0.remote_ip4)
+        gre_if = VppGreInterface(self, self.pg0.local_ip4, self.pg0.remote_ip4)
         gre_if.add_vpp_config()
         gre_if.admin_up()
         gre_if.config_ip4()
 
         # bring the session up now the routes are present
-        self.vpp_session = VppBFDUDPSession(self,
-                                            gre_if,
-                                            gre_if.remote_ip4,
-                                            is_tunnel=True)
+        self.vpp_session = VppBFDUDPSession(
+            self, gre_if, gre_if.remote_ip4, is_tunnel=True
+        )
         self.vpp_session.add_vpp_config()
         self.vpp_session.admin_up()
 
         self.test_session = BFDTestSession(
-            self, gre_if, AF_INET,
-            tunnel_header=(IP(src=self.pg0.remote_ip4,
-                              dst=self.pg0.local_ip4) /
-                           GRE()),
-            phy_interface=self.pg0)
+            self,
+            gre_if,
+            AF_INET,
+            tunnel_header=(IP(src=self.pg0.remote_ip4, dst=self.pg0.local_ip4) / GRE()),
+            phy_interface=self.pg0,
+        )
 
         # packets to match against both of the routes
-        p = [(Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
-              IP(src=self.pg0.remote_ip4, dst=gre_if.remote_ip4) /
-              UDP(sport=1234, dport=1234) /
-              Raw(b'\xa5' * 100))]
+        p = [
+            (
+                Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
+                / IP(src=self.pg0.remote_ip4, dst=gre_if.remote_ip4)
+                / UDP(sport=1234, dport=1234)
+                / Raw(b"\xa5" * 100)
+            )
+        ]
 
         # session is up - traffic passes
         bfd_session_up(self)
@@ -2034,7 +2191,7 @@ class BFDTunTestCase(VppTestCase):
 
 @tag_run_solo
 class BFDSHA1TestCase(VppTestCase):
-    """Bidirectional Forwarding Detection (BFD) (SHA1 auth) """
+    """Bidirectional Forwarding Detection (BFD) (SHA1 auth)"""
 
     pg0 = None
     vpp_clock_offset = None
@@ -2072,31 +2229,39 @@ class BFDSHA1TestCase(VppTestCase):
         super(BFDSHA1TestCase, self).tearDown()
 
     def test_session_up(self):
-        """ bring BFD session up """
+        """bring BFD session up"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4,
-                                            sha1_key=key)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         self.vpp_session.add_vpp_config()
         self.vpp_session.admin_up()
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=self.vpp_session.bfd_key_id)
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key,
+            bfd_key_id=self.vpp_session.bfd_key_id,
+        )
         bfd_session_up(self)
 
     def test_hold_up(self):
-        """ hold BFD session up """
+        """hold BFD session up"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4,
-                                            sha1_key=key)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         self.vpp_session.add_vpp_config()
         self.vpp_session.admin_up()
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=self.vpp_session.bfd_key_id)
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key,
+            bfd_key_id=self.vpp_session.bfd_key_id,
+        )
         bfd_session_up(self)
         for dummy in range(self.test_session.detect_mult * 2):
             wait_for_bfd_packet(self)
@@ -2104,19 +2269,23 @@ class BFDSHA1TestCase(VppTestCase):
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
 
     def test_hold_up_meticulous(self):
-        """ hold BFD session up - meticulous auth """
-        key = self.factory.create_random_key(
-            self, BFDAuthType.meticulous_keyed_sha1)
+        """hold BFD session up - meticulous auth"""
+        key = self.factory.create_random_key(self, BFDAuthType.meticulous_keyed_sha1)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4, sha1_key=key)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         self.vpp_session.add_vpp_config()
         self.vpp_session.admin_up()
         # specify sequence number so that it wraps
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key,
             bfd_key_id=self.vpp_session.bfd_key_id,
-            our_seq_number=0xFFFFFFFF - 4)
+            our_seq_number=0xFFFFFFFF - 4,
+        )
         bfd_session_up(self)
         for dummy in range(30):
             wait_for_bfd_packet(self)
@@ -2125,35 +2294,47 @@ class BFDSHA1TestCase(VppTestCase):
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
 
     def test_send_bad_seq_number(self):
-        """ session is not kept alive by msgs with bad sequence numbers"""
-        key = self.factory.create_random_key(
-            self, BFDAuthType.meticulous_keyed_sha1)
+        """session is not kept alive by msgs with bad sequence numbers"""
+        key = self.factory.create_random_key(self, BFDAuthType.meticulous_keyed_sha1)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4, sha1_key=key)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         self.vpp_session.add_vpp_config()
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=self.vpp_session.bfd_key_id)
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key,
+            bfd_key_id=self.vpp_session.bfd_key_id,
+        )
         bfd_session_up(self)
-        detection_time = self.test_session.detect_mult *\
-            self.vpp_session.required_min_rx / USEC_IN_SEC
+        detection_time = (
+            self.test_session.detect_mult
+            * self.vpp_session.required_min_rx
+            / USEC_IN_SEC
+        )
         send_until = time.time() + 2 * detection_time
         while time.time() < send_until:
             self.test_session.send_packet()
-            self.sleep(0.7 * self.vpp_session.required_min_rx / USEC_IN_SEC,
-                       "time between bfd packets")
+            self.sleep(
+                0.7 * self.vpp_session.required_min_rx / USEC_IN_SEC,
+                "time between bfd packets",
+            )
         e = self.vapi.collect_events()
         # session should be down now, because the sequence numbers weren't
         # updated
         self.assert_equal(len(e), 1, "number of bfd events")
         verify_event(self, e[0], expected_state=BFDState.down)
 
-    def execute_rogue_session_scenario(self, vpp_bfd_udp_session,
-                                       legitimate_test_session,
-                                       rogue_test_session,
-                                       rogue_bfd_values=None):
-        """ execute a rogue session interaction scenario
+    def execute_rogue_session_scenario(
+        self,
+        vpp_bfd_udp_session,
+        legitimate_test_session,
+        rogue_test_session,
+        rogue_bfd_values=None,
+    ):
+        """execute a rogue session interaction scenario
 
         1. create vpp session, add config
         2. bring the legitimate session up
@@ -2178,7 +2359,8 @@ class BFDSHA1TestCase(VppTestCase):
             detect_mult=self.test_session.detect_mult,
             diag=self.test_session.diag,
             state=self.test_session.state,
-            auth_type=self.test_session.auth_type)
+            auth_type=self.test_session.auth_type,
+        )
         if rogue_bfd_values:
             rogue_test_session.update(**rogue_bfd_values)
         rogue_test_session.update(state=BFDState.down)
@@ -2187,69 +2369,84 @@ class BFDSHA1TestCase(VppTestCase):
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
 
     def test_mismatch_auth(self):
-        """ session is not brought down by unauthenticated msg """
+        """session is not brought down by unauthenticated msg"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
         vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4, sha1_key=key)
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         legitimate_test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=vpp_session.bfd_key_id)
+            self, self.pg0, AF_INET, sha1_key=key, bfd_key_id=vpp_session.bfd_key_id
+        )
         rogue_test_session = BFDTestSession(self, self.pg0, AF_INET)
-        self.execute_rogue_session_scenario(vpp_session,
-                                            legitimate_test_session,
-                                            rogue_test_session)
+        self.execute_rogue_session_scenario(
+            vpp_session, legitimate_test_session, rogue_test_session
+        )
 
     def test_mismatch_bfd_key_id(self):
-        """ session is not brought down by msg with non-existent key-id """
+        """session is not brought down by msg with non-existent key-id"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
         vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4, sha1_key=key)
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         # pick a different random bfd key id
         x = randint(0, 255)
         while x == vpp_session.bfd_key_id:
             x = randint(0, 255)
         legitimate_test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=vpp_session.bfd_key_id)
+            self, self.pg0, AF_INET, sha1_key=key, bfd_key_id=vpp_session.bfd_key_id
+        )
         rogue_test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key, bfd_key_id=x)
-        self.execute_rogue_session_scenario(vpp_session,
-                                            legitimate_test_session,
-                                            rogue_test_session)
+            self, self.pg0, AF_INET, sha1_key=key, bfd_key_id=x
+        )
+        self.execute_rogue_session_scenario(
+            vpp_session, legitimate_test_session, rogue_test_session
+        )
 
     def test_mismatched_auth_type(self):
-        """ session is not brought down by msg with wrong auth type """
+        """session is not brought down by msg with wrong auth type"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
         vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4, sha1_key=key)
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         legitimate_test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=vpp_session.bfd_key_id)
+            self, self.pg0, AF_INET, sha1_key=key, bfd_key_id=vpp_session.bfd_key_id
+        )
         rogue_test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=vpp_session.bfd_key_id)
+            self, self.pg0, AF_INET, sha1_key=key, bfd_key_id=vpp_session.bfd_key_id
+        )
         self.execute_rogue_session_scenario(
-            vpp_session, legitimate_test_session, rogue_test_session,
-            {'auth_type': BFDAuthType.keyed_md5})
+            vpp_session,
+            legitimate_test_session,
+            rogue_test_session,
+            {"auth_type": BFDAuthType.keyed_md5},
+        )
 
     def test_restart(self):
-        """ simulate remote peer restart and resynchronization """
-        key = self.factory.create_random_key(
-            self, BFDAuthType.meticulous_keyed_sha1)
+        """simulate remote peer restart and resynchronization"""
+        key = self.factory.create_random_key(self, BFDAuthType.meticulous_keyed_sha1)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4, sha1_key=key)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         self.vpp_session.add_vpp_config()
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=self.vpp_session.bfd_key_id, our_seq_number=0)
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key,
+            bfd_key_id=self.vpp_session.bfd_key_id,
+            our_seq_number=0,
+        )
         bfd_session_up(self)
         # don't send any packets for 2*detection_time
-        detection_time = self.test_session.detect_mult *\
-            self.vpp_session.required_min_rx / USEC_IN_SEC
+        detection_time = (
+            self.test_session.detect_mult
+            * self.vpp_session.required_min_rx
+            / USEC_IN_SEC
+        )
         self.sleep(2 * detection_time, "simulating peer restart")
         events = self.vapi.collect_events()
         self.assert_equal(len(events), 1, "number of bfd events")
@@ -2266,7 +2463,7 @@ class BFDSHA1TestCase(VppTestCase):
 
 @tag_run_solo
 class BFDAuthOnOffTestCase(VppTestCase):
-    """Bidirectional Forwarding Detection (BFD) (changing auth) """
+    """Bidirectional Forwarding Detection (BFD) (changing auth)"""
 
     pg0 = None
     vpp_session = None
@@ -2303,11 +2500,10 @@ class BFDAuthOnOffTestCase(VppTestCase):
         super(BFDAuthOnOffTestCase, self).tearDown()
 
     def test_auth_on_immediate(self):
-        """ turn auth on without disturbing session state (immediate) """
+        """turn auth on without disturbing session state (immediate)"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4)
+        self.vpp_session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
         self.vpp_session.add_vpp_config()
         self.test_session = BFDTestSession(self, self.pg0, AF_INET)
         bfd_session_up(self)
@@ -2323,19 +2519,23 @@ class BFDAuthOnOffTestCase(VppTestCase):
             self.assert_equal(p[BFD].state, BFDState.up, BFDState)
             self.test_session.send_packet()
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
 
     def test_auth_off_immediate(self):
-        """ turn auth off without disturbing session state (immediate) """
+        """turn auth off without disturbing session state (immediate)"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4, sha1_key=key)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         self.vpp_session.add_vpp_config()
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=self.vpp_session.bfd_key_id)
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key,
+            bfd_key_id=self.vpp_session.bfd_key_id,
+        )
         bfd_session_up(self)
         # self.vapi.want_bfd_events(enable_disable=0)
         for dummy in range(self.test_session.detect_mult * 2):
@@ -2352,21 +2552,25 @@ class BFDAuthOnOffTestCase(VppTestCase):
             self.test_session.inc_seq_num()
             self.test_session.send_packet()
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
 
     def test_auth_change_key_immediate(self):
-        """ change auth key without disturbing session state (immediate) """
+        """change auth key without disturbing session state (immediate)"""
         key1 = self.factory.create_random_key(self)
         key1.add_vpp_config()
         key2 = self.factory.create_random_key(self)
         key2.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4, sha1_key=key1)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key1
+        )
         self.vpp_session.add_vpp_config()
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key1,
-            bfd_key_id=self.vpp_session.bfd_key_id)
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key1,
+            bfd_key_id=self.vpp_session.bfd_key_id,
+        )
         bfd_session_up(self)
         for dummy in range(self.test_session.detect_mult * 2):
             p = wait_for_bfd_packet(self)
@@ -2380,15 +2584,13 @@ class BFDAuthOnOffTestCase(VppTestCase):
             self.assert_equal(p[BFD].state, BFDState.up, BFDState)
             self.test_session.send_packet()
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
 
     def test_auth_on_delayed(self):
-        """ turn auth on without disturbing session state (delayed) """
+        """turn auth on without disturbing session state (delayed)"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4)
+        self.vpp_session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
         self.vpp_session.add_vpp_config()
         self.test_session = BFDTestSession(self, self.pg0, AF_INET)
         bfd_session_up(self)
@@ -2408,19 +2610,23 @@ class BFDAuthOnOffTestCase(VppTestCase):
             self.assert_equal(p[BFD].state, BFDState.up, BFDState)
             self.test_session.send_packet()
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
 
     def test_auth_off_delayed(self):
-        """ turn auth off without disturbing session state (delayed) """
+        """turn auth off without disturbing session state (delayed)"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4, sha1_key=key)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         self.vpp_session.add_vpp_config()
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key,
-            bfd_key_id=self.vpp_session.bfd_key_id)
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key,
+            bfd_key_id=self.vpp_session.bfd_key_id,
+        )
         bfd_session_up(self)
         for dummy in range(self.test_session.detect_mult * 2):
             p = wait_for_bfd_packet(self)
@@ -2439,22 +2645,26 @@ class BFDAuthOnOffTestCase(VppTestCase):
             self.assert_equal(p[BFD].state, BFDState.up, BFDState)
             self.test_session.send_packet()
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
 
     def test_auth_change_key_delayed(self):
-        """ change auth key without disturbing session state (delayed) """
+        """change auth key without disturbing session state (delayed)"""
         key1 = self.factory.create_random_key(self)
         key1.add_vpp_config()
         key2 = self.factory.create_random_key(self)
         key2.add_vpp_config()
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip4, sha1_key=key1)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key1
+        )
         self.vpp_session.add_vpp_config()
         self.vpp_session.admin_up()
         self.test_session = BFDTestSession(
-            self, self.pg0, AF_INET, sha1_key=key1,
-            bfd_key_id=self.vpp_session.bfd_key_id)
+            self,
+            self.pg0,
+            AF_INET,
+            sha1_key=key1,
+            bfd_key_id=self.vpp_session.bfd_key_id,
+        )
         bfd_session_up(self)
         for dummy in range(self.test_session.detect_mult * 2):
             p = wait_for_bfd_packet(self)
@@ -2473,13 +2683,13 @@ class BFDAuthOnOffTestCase(VppTestCase):
             self.assert_equal(p[BFD].state, BFDState.up, BFDState)
             self.test_session.send_packet()
         self.assert_equal(self.vpp_session.state, BFDState.up, BFDState)
-        self.assert_equal(len(self.vapi.collect_events()), 0,
-                          "number of bfd events")
+        self.assert_equal(len(self.vapi.collect_events()), 0, "number of bfd events")
 
 
 @tag_run_solo
 class BFDCLITestCase(VppTestCase):
-    """Bidirectional Forwarding Detection (BFD) (CLI) """
+    """Bidirectional Forwarding Detection (BFD) (CLI)"""
+
     pg0 = None
 
     @classmethod
@@ -2516,52 +2726,54 @@ class BFDCLITestCase(VppTestCase):
         super(BFDCLITestCase, self).tearDown()
 
     def cli_verify_no_response(self, cli):
-        """ execute a CLI, asserting that the response is empty """
-        self.assert_equal(self.vapi.cli(cli),
-                          "",
-                          "CLI command response")
+        """execute a CLI, asserting that the response is empty"""
+        self.assert_equal(self.vapi.cli(cli), "", "CLI command response")
 
     def cli_verify_response(self, cli, expected):
-        """ execute a CLI, asserting that the response matches expectation """
+        """execute a CLI, asserting that the response matches expectation"""
         try:
             reply = self.vapi.cli(cli)
         except CliFailedCommandError as cli_error:
             reply = str(cli_error)
-        self.assert_equal(reply.strip(),
-                          expected,
-                          "CLI command response")
+        self.assert_equal(reply.strip(), expected, "CLI command response")
 
     def test_show(self):
-        """ show commands """
+        """show commands"""
         k1 = self.factory.create_random_key(self)
         k1.add_vpp_config()
         k2 = self.factory.create_random_key(
-            self, auth_type=BFDAuthType.meticulous_keyed_sha1)
+            self, auth_type=BFDAuthType.meticulous_keyed_sha1
+        )
         k2.add_vpp_config()
         s1 = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
         s1.add_vpp_config()
-        s2 = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip6, af=AF_INET6,
-                              sha1_key=k2)
+        s2 = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6, sha1_key=k2
+        )
         s2.add_vpp_config()
         self.logger.info(self.vapi.ppcli("show bfd keys"))
         self.logger.info(self.vapi.ppcli("show bfd sessions"))
         self.logger.info(self.vapi.ppcli("show bfd"))
 
     def test_set_del_sha1_key(self):
-        """ set/delete SHA1 auth key """
+        """set/delete SHA1 auth key"""
         k = self.factory.create_random_key(self)
         self.registry.register(k, self.logger)
         self.cli_verify_no_response(
-            "bfd key set conf-key-id %s type keyed-sha1 secret %s" %
-            (k.conf_key_id,
-                "".join("{:02x}".format(scapy.compat.orb(c)) for c in k.key)))
+            "bfd key set conf-key-id %s type keyed-sha1 secret %s"
+            % (
+                k.conf_key_id,
+                "".join("{:02x}".format(scapy.compat.orb(c)) for c in k.key),
+            )
+        )
         self.assertTrue(k.query_vpp_config())
         self.vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4, sha1_key=k)
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=k
+        )
         self.vpp_session.add_vpp_config()
-        self.test_session = \
-            BFDTestSession(self, self.pg0, AF_INET, sha1_key=k,
-                           bfd_key_id=self.vpp_session.bfd_key_id)
+        self.test_session = BFDTestSession(
+            self, self.pg0, AF_INET, sha1_key=k, bfd_key_id=self.vpp_session.bfd_key_id
+        )
         self.vapi.want_bfd_events()
         bfd_session_up(self)
         bfd_session_down(self)
@@ -2569,37 +2781,43 @@ class BFDCLITestCase(VppTestCase):
         # is in-use
         k2 = self.factory.create_random_key(self)
         self.cli_verify_response(
-            "bfd key set conf-key-id %s type keyed-sha1 secret %s" %
-            (k.conf_key_id,
-                "".join("{:02x}".format(scapy.compat.orb(c)) for c in k2.key)),
+            "bfd key set conf-key-id %s type keyed-sha1 secret %s"
+            % (
+                k.conf_key_id,
+                "".join("{:02x}".format(scapy.compat.orb(c)) for c in k2.key),
+            ),
             "bfd key set: `bfd_auth_set_key' API call failed, "
-            "rv=-103:BFD object in use")
+            "rv=-103:BFD object in use",
+        )
         # manipulating the session using old secret should still work
         bfd_session_up(self)
         bfd_session_down(self)
         self.vpp_session.remove_vpp_config()
-        self.cli_verify_no_response(
-            "bfd key del conf-key-id %s" % k.conf_key_id)
+        self.cli_verify_no_response("bfd key del conf-key-id %s" % k.conf_key_id)
         self.assertFalse(k.query_vpp_config())
 
     def test_set_del_meticulous_sha1_key(self):
-        """ set/delete meticulous SHA1 auth key """
+        """set/delete meticulous SHA1 auth key"""
         k = self.factory.create_random_key(
-            self, auth_type=BFDAuthType.meticulous_keyed_sha1)
+            self, auth_type=BFDAuthType.meticulous_keyed_sha1
+        )
         self.registry.register(k, self.logger)
         self.cli_verify_no_response(
-            "bfd key set conf-key-id %s type meticulous-keyed-sha1 secret %s" %
-            (k.conf_key_id,
-                "".join("{:02x}".format(scapy.compat.orb(c)) for c in k.key)))
+            "bfd key set conf-key-id %s type meticulous-keyed-sha1 secret %s"
+            % (
+                k.conf_key_id,
+                "".join("{:02x}".format(scapy.compat.orb(c)) for c in k.key),
+            )
+        )
         self.assertTrue(k.query_vpp_config())
-        self.vpp_session = VppBFDUDPSession(self, self.pg0,
-                                            self.pg0.remote_ip6, af=AF_INET6,
-                                            sha1_key=k)
+        self.vpp_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6, sha1_key=k
+        )
         self.vpp_session.add_vpp_config()
         self.vpp_session.admin_up()
-        self.test_session = \
-            BFDTestSession(self, self.pg0, AF_INET6, sha1_key=k,
-                           bfd_key_id=self.vpp_session.bfd_key_id)
+        self.test_session = BFDTestSession(
+            self, self.pg0, AF_INET6, sha1_key=k, bfd_key_id=self.vpp_session.bfd_key_id
+        )
         self.vapi.want_bfd_events()
         bfd_session_up(self)
         bfd_session_down(self)
@@ -2607,299 +2825,409 @@ class BFDCLITestCase(VppTestCase):
         # is in-use
         k2 = self.factory.create_random_key(self)
         self.cli_verify_response(
-            "bfd key set conf-key-id %s type keyed-sha1 secret %s" %
-            (k.conf_key_id,
-                "".join("{:02x}".format(scapy.compat.orb(c)) for c in k2.key)),
+            "bfd key set conf-key-id %s type keyed-sha1 secret %s"
+            % (
+                k.conf_key_id,
+                "".join("{:02x}".format(scapy.compat.orb(c)) for c in k2.key),
+            ),
             "bfd key set: `bfd_auth_set_key' API call failed, "
-            "rv=-103:BFD object in use")
+            "rv=-103:BFD object in use",
+        )
         # manipulating the session using old secret should still work
         bfd_session_up(self)
         bfd_session_down(self)
         self.vpp_session.remove_vpp_config()
-        self.cli_verify_no_response(
-            "bfd key del conf-key-id %s" % k.conf_key_id)
+        self.cli_verify_no_response("bfd key del conf-key-id %s" % k.conf_key_id)
         self.assertFalse(k.query_vpp_config())
 
     def test_add_mod_del_bfd_udp(self):
-        """ create/modify/delete IPv4 BFD UDP session """
-        vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4)
+        """create/modify/delete IPv4 BFD UDP session"""
+        vpp_session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
         self.registry.register(vpp_session, self.logger)
-        cli_add_cmd = "bfd udp session add interface %s local-addr %s " \
-            "peer-addr %s desired-min-tx %s required-min-rx %s "\
-            "detect-mult %s" % (self.pg0.name, self.pg0.local_ip4,
-                                self.pg0.remote_ip4,
-                                vpp_session.desired_min_tx,
-                                vpp_session.required_min_rx,
-                                vpp_session.detect_mult)
+        cli_add_cmd = (
+            "bfd udp session add interface %s local-addr %s "
+            "peer-addr %s desired-min-tx %s required-min-rx %s "
+            "detect-mult %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip4,
+                self.pg0.remote_ip4,
+                vpp_session.desired_min_tx,
+                vpp_session.required_min_rx,
+                vpp_session.detect_mult,
+            )
+        )
         self.cli_verify_no_response(cli_add_cmd)
         # 2nd add should fail
         self.cli_verify_response(
             cli_add_cmd,
             "bfd udp session add: `bfd_add_add_session' API call"
-            " failed, rv=-101:Duplicate BFD object")
+            " failed, rv=-101:Duplicate BFD object",
+        )
         verify_bfd_session_config(self, vpp_session)
         mod_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4,
+            self,
+            self.pg0,
+            self.pg0.remote_ip4,
             required_min_rx=2 * vpp_session.required_min_rx,
             desired_min_tx=3 * vpp_session.desired_min_tx,
-            detect_mult=4 * vpp_session.detect_mult)
+            detect_mult=4 * vpp_session.detect_mult,
+        )
         self.cli_verify_no_response(
             "bfd udp session mod interface %s local-addr %s peer-addr %s "
-            "desired-min-tx %s required-min-rx %s detect-mult %s" %
-            (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4,
-             mod_session.desired_min_tx, mod_session.required_min_rx,
-             mod_session.detect_mult))
+            "desired-min-tx %s required-min-rx %s detect-mult %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip4,
+                self.pg0.remote_ip4,
+                mod_session.desired_min_tx,
+                mod_session.required_min_rx,
+                mod_session.detect_mult,
+            )
+        )
         verify_bfd_session_config(self, mod_session)
-        cli_del_cmd = "bfd udp session del interface %s local-addr %s "\
-            "peer-addr %s" % (self.pg0.name,
-                              self.pg0.local_ip4, self.pg0.remote_ip4)
+        cli_del_cmd = (
+            "bfd udp session del interface %s local-addr %s "
+            "peer-addr %s" % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
+        )
         self.cli_verify_no_response(cli_del_cmd)
         # 2nd del is expected to fail
         self.cli_verify_response(
-            cli_del_cmd, "bfd udp session del: `bfd_udp_del_session' API call"
-            " failed, rv=-102:No such BFD object")
+            cli_del_cmd,
+            "bfd udp session del: `bfd_udp_del_session' API call"
+            " failed, rv=-102:No such BFD object",
+        )
         self.assertFalse(vpp_session.query_vpp_config())
 
     def test_add_mod_del_bfd_udp6(self):
-        """ create/modify/delete IPv6 BFD UDP session """
-        vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6)
+        """create/modify/delete IPv6 BFD UDP session"""
+        vpp_session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip6, af=AF_INET6)
         self.registry.register(vpp_session, self.logger)
-        cli_add_cmd = "bfd udp session add interface %s local-addr %s " \
-            "peer-addr %s desired-min-tx %s required-min-rx %s "\
-            "detect-mult %s" % (self.pg0.name, self.pg0.local_ip6,
-                                self.pg0.remote_ip6,
-                                vpp_session.desired_min_tx,
-                                vpp_session.required_min_rx,
-                                vpp_session.detect_mult)
+        cli_add_cmd = (
+            "bfd udp session add interface %s local-addr %s "
+            "peer-addr %s desired-min-tx %s required-min-rx %s "
+            "detect-mult %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip6,
+                self.pg0.remote_ip6,
+                vpp_session.desired_min_tx,
+                vpp_session.required_min_rx,
+                vpp_session.detect_mult,
+            )
+        )
         self.cli_verify_no_response(cli_add_cmd)
         # 2nd add should fail
         self.cli_verify_response(
             cli_add_cmd,
             "bfd udp session add: `bfd_add_add_session' API call"
-            " failed, rv=-101:Duplicate BFD object")
+            " failed, rv=-101:Duplicate BFD object",
+        )
         verify_bfd_session_config(self, vpp_session)
         mod_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6,
+            self,
+            self.pg0,
+            self.pg0.remote_ip6,
+            af=AF_INET6,
             required_min_rx=2 * vpp_session.required_min_rx,
             desired_min_tx=3 * vpp_session.desired_min_tx,
-            detect_mult=4 * vpp_session.detect_mult)
+            detect_mult=4 * vpp_session.detect_mult,
+        )
         self.cli_verify_no_response(
             "bfd udp session mod interface %s local-addr %s peer-addr %s "
-            "desired-min-tx %s required-min-rx %s detect-mult %s" %
-            (self.pg0.name, self.pg0.local_ip6, self.pg0.remote_ip6,
-             mod_session.desired_min_tx,
-             mod_session.required_min_rx, mod_session.detect_mult))
+            "desired-min-tx %s required-min-rx %s detect-mult %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip6,
+                self.pg0.remote_ip6,
+                mod_session.desired_min_tx,
+                mod_session.required_min_rx,
+                mod_session.detect_mult,
+            )
+        )
         verify_bfd_session_config(self, mod_session)
-        cli_del_cmd = "bfd udp session del interface %s local-addr %s "\
-            "peer-addr %s" % (self.pg0.name,
-                              self.pg0.local_ip6, self.pg0.remote_ip6)
+        cli_del_cmd = (
+            "bfd udp session del interface %s local-addr %s "
+            "peer-addr %s" % (self.pg0.name, self.pg0.local_ip6, self.pg0.remote_ip6)
+        )
         self.cli_verify_no_response(cli_del_cmd)
         # 2nd del is expected to fail
         self.cli_verify_response(
             cli_del_cmd,
             "bfd udp session del: `bfd_udp_del_session' API call"
-            " failed, rv=-102:No such BFD object")
+            " failed, rv=-102:No such BFD object",
+        )
         self.assertFalse(vpp_session.query_vpp_config())
 
     def test_add_mod_del_bfd_udp_auth(self):
-        """ create/modify/delete IPv4 BFD UDP session (authenticated) """
+        """create/modify/delete IPv4 BFD UDP session (authenticated)"""
         key = self.factory.create_random_key(self)
         key.add_vpp_config()
         vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4, sha1_key=key)
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         self.registry.register(vpp_session, self.logger)
-        cli_add_cmd = "bfd udp session add interface %s local-addr %s " \
-            "peer-addr %s desired-min-tx %s required-min-rx %s "\
-            "detect-mult %s conf-key-id %s bfd-key-id %s"\
-            % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4,
-               vpp_session.desired_min_tx, vpp_session.required_min_rx,
-               vpp_session.detect_mult, key.conf_key_id,
-               vpp_session.bfd_key_id)
+        cli_add_cmd = (
+            "bfd udp session add interface %s local-addr %s "
+            "peer-addr %s desired-min-tx %s required-min-rx %s "
+            "detect-mult %s conf-key-id %s bfd-key-id %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip4,
+                self.pg0.remote_ip4,
+                vpp_session.desired_min_tx,
+                vpp_session.required_min_rx,
+                vpp_session.detect_mult,
+                key.conf_key_id,
+                vpp_session.bfd_key_id,
+            )
+        )
         self.cli_verify_no_response(cli_add_cmd)
         # 2nd add should fail
         self.cli_verify_response(
             cli_add_cmd,
             "bfd udp session add: `bfd_add_add_session' API call"
-            " failed, rv=-101:Duplicate BFD object")
+            " failed, rv=-101:Duplicate BFD object",
+        )
         verify_bfd_session_config(self, vpp_session)
         mod_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip4, sha1_key=key,
+            self,
+            self.pg0,
+            self.pg0.remote_ip4,
+            sha1_key=key,
             bfd_key_id=vpp_session.bfd_key_id,
             required_min_rx=2 * vpp_session.required_min_rx,
             desired_min_tx=3 * vpp_session.desired_min_tx,
-            detect_mult=4 * vpp_session.detect_mult)
+            detect_mult=4 * vpp_session.detect_mult,
+        )
         self.cli_verify_no_response(
             "bfd udp session mod interface %s local-addr %s peer-addr %s "
-            "desired-min-tx %s required-min-rx %s detect-mult %s" %
-            (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4,
-             mod_session.desired_min_tx,
-             mod_session.required_min_rx, mod_session.detect_mult))
+            "desired-min-tx %s required-min-rx %s detect-mult %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip4,
+                self.pg0.remote_ip4,
+                mod_session.desired_min_tx,
+                mod_session.required_min_rx,
+                mod_session.detect_mult,
+            )
+        )
         verify_bfd_session_config(self, mod_session)
-        cli_del_cmd = "bfd udp session del interface %s local-addr %s "\
-            "peer-addr %s" % (self.pg0.name,
-                              self.pg0.local_ip4, self.pg0.remote_ip4)
+        cli_del_cmd = (
+            "bfd udp session del interface %s local-addr %s "
+            "peer-addr %s" % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
+        )
         self.cli_verify_no_response(cli_del_cmd)
         # 2nd del is expected to fail
         self.cli_verify_response(
             cli_del_cmd,
             "bfd udp session del: `bfd_udp_del_session' API call"
-            " failed, rv=-102:No such BFD object")
+            " failed, rv=-102:No such BFD object",
+        )
         self.assertFalse(vpp_session.query_vpp_config())
 
     def test_add_mod_del_bfd_udp6_auth(self):
-        """ create/modify/delete IPv6 BFD UDP session (authenticated) """
+        """create/modify/delete IPv6 BFD UDP session (authenticated)"""
         key = self.factory.create_random_key(
-            self, auth_type=BFDAuthType.meticulous_keyed_sha1)
+            self, auth_type=BFDAuthType.meticulous_keyed_sha1
+        )
         key.add_vpp_config()
         vpp_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6, sha1_key=key)
+            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6, sha1_key=key
+        )
         self.registry.register(vpp_session, self.logger)
-        cli_add_cmd = "bfd udp session add interface %s local-addr %s " \
-            "peer-addr %s desired-min-tx %s required-min-rx %s "\
-            "detect-mult %s conf-key-id %s bfd-key-id %s" \
-            % (self.pg0.name, self.pg0.local_ip6, self.pg0.remote_ip6,
-               vpp_session.desired_min_tx, vpp_session.required_min_rx,
-               vpp_session.detect_mult, key.conf_key_id,
-               vpp_session.bfd_key_id)
+        cli_add_cmd = (
+            "bfd udp session add interface %s local-addr %s "
+            "peer-addr %s desired-min-tx %s required-min-rx %s "
+            "detect-mult %s conf-key-id %s bfd-key-id %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip6,
+                self.pg0.remote_ip6,
+                vpp_session.desired_min_tx,
+                vpp_session.required_min_rx,
+                vpp_session.detect_mult,
+                key.conf_key_id,
+                vpp_session.bfd_key_id,
+            )
+        )
         self.cli_verify_no_response(cli_add_cmd)
         # 2nd add should fail
         self.cli_verify_response(
             cli_add_cmd,
             "bfd udp session add: `bfd_add_add_session' API call"
-            " failed, rv=-101:Duplicate BFD object")
+            " failed, rv=-101:Duplicate BFD object",
+        )
         verify_bfd_session_config(self, vpp_session)
         mod_session = VppBFDUDPSession(
-            self, self.pg0, self.pg0.remote_ip6, af=AF_INET6, sha1_key=key,
+            self,
+            self.pg0,
+            self.pg0.remote_ip6,
+            af=AF_INET6,
+            sha1_key=key,
             bfd_key_id=vpp_session.bfd_key_id,
             required_min_rx=2 * vpp_session.required_min_rx,
             desired_min_tx=3 * vpp_session.desired_min_tx,
-            detect_mult=4 * vpp_session.detect_mult)
+            detect_mult=4 * vpp_session.detect_mult,
+        )
         self.cli_verify_no_response(
             "bfd udp session mod interface %s local-addr %s peer-addr %s "
-            "desired-min-tx %s required-min-rx %s detect-mult %s" %
-            (self.pg0.name, self.pg0.local_ip6, self.pg0.remote_ip6,
-             mod_session.desired_min_tx,
-             mod_session.required_min_rx, mod_session.detect_mult))
+            "desired-min-tx %s required-min-rx %s detect-mult %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip6,
+                self.pg0.remote_ip6,
+                mod_session.desired_min_tx,
+                mod_session.required_min_rx,
+                mod_session.detect_mult,
+            )
+        )
         verify_bfd_session_config(self, mod_session)
-        cli_del_cmd = "bfd udp session del interface %s local-addr %s "\
-            "peer-addr %s" % (self.pg0.name,
-                              self.pg0.local_ip6, self.pg0.remote_ip6)
+        cli_del_cmd = (
+            "bfd udp session del interface %s local-addr %s "
+            "peer-addr %s" % (self.pg0.name, self.pg0.local_ip6, self.pg0.remote_ip6)
+        )
         self.cli_verify_no_response(cli_del_cmd)
         # 2nd del is expected to fail
         self.cli_verify_response(
             cli_del_cmd,
             "bfd udp session del: `bfd_udp_del_session' API call"
-            " failed, rv=-102:No such BFD object")
+            " failed, rv=-102:No such BFD object",
+        )
         self.assertFalse(vpp_session.query_vpp_config())
 
     def test_auth_on_off(self):
-        """ turn authentication on and off """
+        """turn authentication on and off"""
         key = self.factory.create_random_key(
-            self, auth_type=BFDAuthType.meticulous_keyed_sha1)
+            self, auth_type=BFDAuthType.meticulous_keyed_sha1
+        )
         key.add_vpp_config()
         session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
-        auth_session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4,
-                                        sha1_key=key)
+        auth_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         session.add_vpp_config()
-        cli_activate = \
-            "bfd udp session auth activate interface %s local-addr %s "\
-            "peer-addr %s conf-key-id %s bfd-key-id %s"\
-            % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4,
-               key.conf_key_id, auth_session.bfd_key_id)
+        cli_activate = (
+            "bfd udp session auth activate interface %s local-addr %s "
+            "peer-addr %s conf-key-id %s bfd-key-id %s"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip4,
+                self.pg0.remote_ip4,
+                key.conf_key_id,
+                auth_session.bfd_key_id,
+            )
+        )
         self.cli_verify_no_response(cli_activate)
         verify_bfd_session_config(self, auth_session)
         self.cli_verify_no_response(cli_activate)
         verify_bfd_session_config(self, auth_session)
-        cli_deactivate = \
-            "bfd udp session auth deactivate interface %s local-addr %s "\
-            "peer-addr %s "\
-            % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
+        cli_deactivate = (
+            "bfd udp session auth deactivate interface %s local-addr %s "
+            "peer-addr %s " % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
+        )
         self.cli_verify_no_response(cli_deactivate)
         verify_bfd_session_config(self, session)
         self.cli_verify_no_response(cli_deactivate)
         verify_bfd_session_config(self, session)
 
     def test_auth_on_off_delayed(self):
-        """ turn authentication on and off (delayed) """
+        """turn authentication on and off (delayed)"""
         key = self.factory.create_random_key(
-            self, auth_type=BFDAuthType.meticulous_keyed_sha1)
+            self, auth_type=BFDAuthType.meticulous_keyed_sha1
+        )
         key.add_vpp_config()
         session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
-        auth_session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4,
-                                        sha1_key=key)
+        auth_session = VppBFDUDPSession(
+            self, self.pg0, self.pg0.remote_ip4, sha1_key=key
+        )
         session.add_vpp_config()
-        cli_activate = \
-            "bfd udp session auth activate interface %s local-addr %s "\
-            "peer-addr %s conf-key-id %s bfd-key-id %s delayed yes"\
-            % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4,
-               key.conf_key_id, auth_session.bfd_key_id)
+        cli_activate = (
+            "bfd udp session auth activate interface %s local-addr %s "
+            "peer-addr %s conf-key-id %s bfd-key-id %s delayed yes"
+            % (
+                self.pg0.name,
+                self.pg0.local_ip4,
+                self.pg0.remote_ip4,
+                key.conf_key_id,
+                auth_session.bfd_key_id,
+            )
+        )
         self.cli_verify_no_response(cli_activate)
         verify_bfd_session_config(self, auth_session)
         self.cli_verify_no_response(cli_activate)
         verify_bfd_session_config(self, auth_session)
-        cli_deactivate = \
-            "bfd udp session auth deactivate interface %s local-addr %s "\
-            "peer-addr %s delayed yes"\
+        cli_deactivate = (
+            "bfd udp session auth deactivate interface %s local-addr %s "
+            "peer-addr %s delayed yes"
             % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
+        )
         self.cli_verify_no_response(cli_deactivate)
         verify_bfd_session_config(self, session)
         self.cli_verify_no_response(cli_deactivate)
         verify_bfd_session_config(self, session)
 
     def test_admin_up_down(self):
-        """ put session admin-up and admin-down """
+        """put session admin-up and admin-down"""
         session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
         session.add_vpp_config()
-        cli_down = \
-            "bfd udp session set-flags admin down interface %s local-addr %s "\
-            "peer-addr %s "\
-            % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
-        cli_up = \
-            "bfd udp session set-flags admin up interface %s local-addr %s "\
-            "peer-addr %s "\
-            % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
+        cli_down = (
+            "bfd udp session set-flags admin down interface %s local-addr %s "
+            "peer-addr %s " % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
+        )
+        cli_up = (
+            "bfd udp session set-flags admin up interface %s local-addr %s "
+            "peer-addr %s " % (self.pg0.name, self.pg0.local_ip4, self.pg0.remote_ip4)
+        )
         self.cli_verify_no_response(cli_down)
         verify_bfd_session_config(self, session, state=BFDState.admin_down)
         self.cli_verify_no_response(cli_up)
         verify_bfd_session_config(self, session, state=BFDState.down)
 
     def test_set_del_udp_echo_source(self):
-        """ set/del udp echo source """
+        """set/del udp echo source"""
         self.create_loopback_interfaces(1)
         self.loopback0 = self.lo_interfaces[0]
         self.loopback0.admin_up()
-        self.cli_verify_response("show bfd echo-source",
-                                 "UDP echo source is not set.")
+        self.cli_verify_response("show bfd echo-source", "UDP echo source is not set.")
         cli_set = "bfd udp echo-source set interface %s" % self.loopback0.name
         self.cli_verify_no_response(cli_set)
-        self.cli_verify_response("show bfd echo-source",
-                                 "UDP echo source is: %s\n"
-                                 "IPv4 address usable as echo source: none\n"
-                                 "IPv6 address usable as echo source: none" %
-                                 self.loopback0.name)
+        self.cli_verify_response(
+            "show bfd echo-source",
+            "UDP echo source is: %s\n"
+            "IPv4 address usable as echo source: none\n"
+            "IPv6 address usable as echo source: none" % self.loopback0.name,
+        )
         self.loopback0.config_ip4()
-        echo_ip4 = str(ipaddress.IPv4Address(int(ipaddress.IPv4Address(
-            self.loopback0.local_ip4)) ^ 1))
-        self.cli_verify_response("show bfd echo-source",
-                                 "UDP echo source is: %s\n"
-                                 "IPv4 address usable as echo source: %s\n"
-                                 "IPv6 address usable as echo source: none" %
-                                 (self.loopback0.name, echo_ip4))
-        echo_ip6 = str(ipaddress.IPv6Address(int(ipaddress.IPv6Address(
-            self.loopback0.local_ip6)) ^ 1))
+        echo_ip4 = str(
+            ipaddress.IPv4Address(
+                int(ipaddress.IPv4Address(self.loopback0.local_ip4)) ^ 1
+            )
+        )
+        self.cli_verify_response(
+            "show bfd echo-source",
+            "UDP echo source is: %s\n"
+            "IPv4 address usable as echo source: %s\n"
+            "IPv6 address usable as echo source: none"
+            % (self.loopback0.name, echo_ip4),
+        )
+        echo_ip6 = str(
+            ipaddress.IPv6Address(
+                int(ipaddress.IPv6Address(self.loopback0.local_ip6)) ^ 1
+            )
+        )
         self.loopback0.config_ip6()
-        self.cli_verify_response("show bfd echo-source",
-                                 "UDP echo source is: %s\n"
-                                 "IPv4 address usable as echo source: %s\n"
-                                 "IPv6 address usable as echo source: %s" %
-                                 (self.loopback0.name, echo_ip4, echo_ip6))
+        self.cli_verify_response(
+            "show bfd echo-source",
+            "UDP echo source is: %s\n"
+            "IPv4 address usable as echo source: %s\n"
+            "IPv6 address usable as echo source: %s"
+            % (self.loopback0.name, echo_ip4, echo_ip6),
+        )
         cli_del = "bfd udp echo-source del"
         self.cli_verify_no_response(cli_del)
-        self.cli_verify_response("show bfd echo-source",
-                                 "UDP echo source is not set.")
+        self.cli_verify_response("show bfd echo-source", "UDP echo source is not set.")
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main(testRunner=VppTestRunner)