Unexpected Behaviour using unittest

[Bruce Coram]

The code fragment below shows what appears to be inconsistent
behaviour. The code is testing that messages are created correctly and
that an instances of a class is created correctly. It checks that all
of the expected addresses are used (contained in addresslist) and that
all of the messages are used (contained in msglist). If the data in
msglist that appears in the list in the dictionary whose first key is
'Sonar Main' is a simple list of two items the test behaves as expected
and passes. However, if the data is enclosed within a tuple such that
the list only contains the tuple, which contains the two values, the
test fails. The first of these two values is a class object and the
code tests whether the instance of this class is created correctly
locally and that test is passed in both cases. The test fails because
the msglist item for 'Sonar Main' is not deleted. I have included an
example of the 'Sonar Main' data and also the test output. I can not
explain this behaviour and while it is not a showstopper I need to
understand why. The same behaviour is shown elsewhere if a list of four
items is grouped into two tuples each of two items. Grateful for any
comments/explanations.

CODE FRAGMENT:

msglist = [{'Helm': {'init': (80, 80, 0, 12, 140, 20)}},
{'UAW Director': {'init': (80, 80, 0, 12, 140, 20),
'sonar_a': ['std'], 'sub_attack': ['std']}},
{'Gun Director': {'guns_s': ['std'], 'init': (80, 80, 0, 12,
140, 20), 'guns_mr': ['std'], 'guns_aa': ['std']}},
{'Sonar Main': {'sonar_s': [DummySonar, 0]}}, {'Surface Radar
Operator': {'radar_s': ['std']}}]
addresslist = ['127.10.2.2', '127.10.2.1', '127.10.2.5',
'127.10.2.4', '127.10.2.3']
for entry in msgs:
if entry[1] in addresslist:
addresslist.remove(entry[1])
if entry[0]['set role'] in msglist:
if entry[0]['set role'].keys() == ['Sonar Main']:
print 'keys = ', entry[0]['set role'].keys()
if not
isinstance(self.newprocessor.vessel.uwsearch.sonar_search,
shipserverclasses.DummySonar):
Pass = False
print '1',
type(self.newprocessor.vessel.uwsearch.sonar_search)
print 'removing msg ', entry[0]['set role']
msglist.remove(entry[0]['set role'])
else:
print 'removing msg ', entry[0]['set role']
msglist.remove(entry[0]['set role'])
if addresslist != []:
Pass = False
print '2', addresslist
if msglist != []:
Pass = False
print '3', msglist
self.failUnless(Pass == True)

------------------------------------------------------------------------------------------------

Data fragment - passed:

{'Sonar Main': {'sonar_s': [DummySonar, 0]}}

Test Output:

testAllConnectedUWsearchChange2
(__main__.TestMsgProcessesShipServerSetType) ...
removing msg {'Helm': {'init': (80, 80, 0, 12, 140, 20)}}
removing msg {'UAW Director': {'init': (80, 80, 0, 12, 140, 20),
'sonar_a': ['s
td'], 'sub_attack': ['std']}}
keys = ['Sonar Main']
removing msg {'Sonar Main': {'sonar_s': [<class
'shipserverclasses.DummySonar'>
, 0]}}
removing msg {'Gun Director': {'guns_s': ['std'], 'init': (80, 80, 0,
12, 140,
20), 'guns_mr': ['std'], 'guns_aa': ['std']}}
removing msg {'Surface Radar Operator': {'radar_s': ['std']}}
ok

------------------------------------------------------------------------------------------------------

Data fragment - failed:

{'Sonar Main': {'sonar_s': [(DummySonar, 0)]}}

Test Output:

testAllConnectedUWsearchChange2
(__main__.TestMsgProcessesShipServerSetType) ...
removing msg {'Helm': {'init': (80, 80, 0, 12, 140, 20)}}
removing msg {'UAW Director': {'init': (80, 80, 0, 12, 140, 20),
'sonar_a': ['s
td'], 'sub_attack': ['std']}}
removing msg {'Gun Director': {'guns_s': ['std'], 'init': (80, 80, 0,
12, 140,
20), 'guns_mr': ['std'], 'guns_aa': ['std']}}
removing msg {'Surface Radar Operator': {'radar_s': ['std']}}
3 [{'Sonar Main': {'sonar_s': [(<class 'shipserverclasses.DummySonar'>,
0)]}}]
FAIL