Fixed simplecyclic test

Originally, the testcase would fail because timestamps would not match.
This was due to a Can.Message being initialized had a timestamp
value of 0, while a recv'd message had a virtual timestamp. When compared
they never matched.

Modified testcase now allows for some variation (0.016 s) in the timestamp
for a 0.01 s periodic message and compares the last message with the next
last message.

Author: bhass1

test/simplecyclic_test.py

@@ -20,7 +20,7 @@ class SimpleCyclicSendTaskTest(unittest.TestCase, ComparingMessagesTestCase):
 
     def __init__(self, *args, **kwargs):
         unittest.TestCase.__init__(self, *args, **kwargs)
-        ComparingMessagesTestCase.__init__(self, allowed_timestamp_delta=None, preserves_channel=True)
+        ComparingMessagesTestCase.__init__(self, allowed_timestamp_delta=0.016, preserves_channel=True)
 
     @unittest.skipIf(IS_CI, "the timing sensitive behaviour cannot be reproduced reliably on a CI server")
     def test_cycle_time(self):
@@ -36,7 +36,8 @@ def test_cycle_time(self):
         self.assertTrue(80 <= size <= 120,
                         '100 +/- 20 messages should have been transmitted. But queue contained {}'.format(size))
         last_msg = bus2.recv()
-        self.assertMessageEqual(last_msg, msg)
+        next_last_msg = bus2.recv()
+        self.assertMessageEqual(last_msg, next_last_msg)
 
         bus1.shutdown()
         bus2.shutdown()