make test: improve robustness and performance

Introduce an API which asserts empty capture for interface.
Throw exception in old API if the capture does not exist, thus
making it clear if the test expects packets to arrive or not.
Improve performance by not doing sleeps after starting the packet
generator, rather lazily deleting captures when needed.
Fix wrong usage of packet.show() in various tests.

Change-Id: I456cb23316eef99b3f35f80344fe595c4db9a21c
Signed-off-by: Klement Sekera <ksekera@cisco.com>

1 files changed, 30 insertions, 11 deletions

diff --git a/test/framework.py b/test/framework.py
index 2618b267..1c3e56cc 100644
--- a/test/framework.py
+++ b/test/framework.py
@@ -5,7 +5,6 @@ import unittest
 import tempfile
 import time
 import resource
-from time import sleep
 from collections import deque
 from threading import Thread
 from inspect import getdoc
@@ -181,7 +180,8 @@ class VppTestCase(unittest.TestCase):
         cls.logger.info("Temporary dir is %s, shm prefix is %s",
                         cls.tempdir, cls.shm_prefix)
         cls.setUpConstants()
-        cls.pg_streams = []
+        cls._captures = []
+        cls._zombie_captures = []
         cls.packet_infos = {}
         cls.verbose = 0
         cls.vpp_dead = False
@@ -312,17 +312,36 @@ class VppTestCase(unittest.TestCase):
             i.enable_capture()
 
     @classmethod
-    def pg_start(cls, sleep_time=1):
-        """
-        Enable the packet-generator and send all prepared packet streams
-        Remove the packet streams afterwards
-        """
+    def register_capture(cls, cap_name):
+        """ Register a capture in the testclass """
+        # add to the list of captures with current timestamp
+        cls._captures.append((time.time(), cap_name))
+        # filter out from zombies
+        cls._zombie_captures = [(stamp, name)
+                                for (stamp, name) in cls._zombie_captures
+                                if name != cap_name]
+
+    @classmethod
+    def pg_start(cls):
+        """ Remove any zombie captures and enable the packet generator """
+        # how long before capture is allowed to be deleted - otherwise vpp
+        # crashes - 100ms seems enough (this shouldn't be needed at all)
+        capture_ttl = 0.1
+        now = time.time()
+        for stamp, cap_name in cls._zombie_captures:
+            wait = stamp + capture_ttl - now
+            if wait > 0:
+                cls.logger.debug("Waiting for %ss before deleting capture %s",
+                                 wait, cap_name)
+                time.sleep(wait)
+                now = time.time()
+            cls.logger.debug("Removing zombie capture %s" % cap_name)
+            cls.vapi.cli('packet-generator delete %s' % cap_name)
+
         cls.vapi.cli("trace add pg-input 50")  # 50 is maximum
         cls.vapi.cli('packet-generator enable')
-        sleep(sleep_time)  # give VPP some time to process the packets
-        for stream in cls.pg_streams:
-            cls.vapi.cli('packet-generator delete %s' % stream)
-        cls.pg_streams = []
+        cls._zombie_captures = cls._captures
+        cls._captures = []
 
     @classmethod
     def create_pg_interfaces(cls, interfaces):