make test: improve handling of packet captures

Perform accounting of expected packets based on created packet infos.
Use this accounting info to automatically expect (and verify) the
correct number of packets to be captured. Automatically retry the read
of the capture file if scapy raises an exception while doing so to
handle rare cases when capture file is read while only partially
written during busy wait. Don't fail assert_nothing_captured if only
junk packets arrived.

Change-Id: I16ec2e9410ef510d313ec16b7e13c57d0b2a63f5
Signed-off-by: Klement Sekera <ksekera@cisco.com>

1 files changed, 32 insertions, 21 deletions

diff --git a/test/framework.py b/test/framework.py
index 1b745ff3..324a64ce 100644
--- a/test/framework.py
+++ b/test/framework.py
@@ -10,6 +10,7 @@ from threading import Thread
 from inspect import getdoc
 from hook import StepHook, PollHook
 from vpp_pg_interface import VppPGInterface
+from vpp_sub_interface import VppSubInterface
 from vpp_lo_interface import VppLoInterface
 from vpp_papi_provider import VppPapiProvider
 from scapy.packet import Raw
@@ -63,9 +64,13 @@ class VppTestCase(unittest.TestCase):
         """List of packet infos"""
         return self._packet_infos
 
-    @packet_infos.setter
-    def packet_infos(self, value):
-        self._packet_infos = value
+    @classmethod
+    def get_packet_count_for_if_idx(cls, dst_if_index):
+        """Get the number of packet info for specified destination if index"""
+        if dst_if_index in cls._packet_count_for_dst_if_idx:
+            return cls._packet_count_for_dst_if_idx[dst_if_index]
+        else:
+            return 0
 
     @classmethod
     def instance(cls):
@@ -184,9 +189,9 @@ class VppTestCase(unittest.TestCase):
         cls.logger.info("Temporary dir is %s, shm prefix is %s",
                         cls.tempdir, cls.shm_prefix)
         cls.setUpConstants()
+        cls.reset_packet_infos()
         cls._captures = []
         cls._zombie_captures = []
-        cls.packet_infos = {}
         cls.verbose = 0
         cls.vpp_dead = False
         print(double_line_delim)
@@ -394,31 +399,37 @@ class VppTestCase(unittest.TestCase):
         if extend > 0:
             packet[Raw].load += ' ' * extend
 
-    def add_packet_info_to_list(self, info):
-        """
-        Add packet info to the testcase's packet info list
-
-        :param info: packet info
-
-        """
-        info.index = len(self.packet_infos)
-        self.packet_infos[info.index] = info
+    @classmethod
+    def reset_packet_infos(cls):
+        """ Reset the list of packet info objects and packet counts to zero """
+        cls._packet_infos = {}
+        cls._packet_count_for_dst_if_idx = {}
 
-    def create_packet_info(self, src_pg_index, dst_pg_index):
+    @classmethod
+    def create_packet_info(cls, src_if, dst_if):
         """
         Create packet info object containing the source and destination indexes
         and add it to the testcase's packet info list
 
-        :param src_pg_index: source packet-generator index
-        :param dst_pg_index: destination packet-generator index
+        :param VppInterface src_if: source interface
+        :param VppInterface dst_if: destination interface
 
         :returns: _PacketInfo object
 
         """
         info = _PacketInfo()
-        self.add_packet_info_to_list(info)
-        info.src = src_pg_index
-        info.dst = dst_pg_index
+        info.index = len(cls._packet_infos)
+        info.src = src_if.sw_if_index
+        info.dst = dst_if.sw_if_index
+        if isinstance(dst_if, VppSubInterface):
+            dst_idx = dst_if.parent.sw_if_index
+        else:
+            dst_idx = dst_if.sw_if_index
+        if dst_idx in cls._packet_count_for_dst_if_idx:
+            cls._packet_count_for_dst_if_idx[dst_idx] += 1
+        else:
+            cls._packet_count_for_dst_if_idx[dst_idx] = 1
+        cls._packet_infos[info.index] = info
         return info
 
     @staticmethod
@@ -462,10 +473,10 @@ class VppTestCase(unittest.TestCase):
             next_index = 0
         else:
             next_index = info.index + 1
-        if next_index == len(self.packet_infos):
+        if next_index == len(self._packet_infos):
             return None
         else:
-            return self.packet_infos[next_index]
+            return self._packet_infos[next_index]
 
     def get_next_packet_info_for_interface(self, src_index, info):
         """