Why does a failing test with mox fail other tests as well?

Question

My issue is quite simple: I'm having a bunch of unit tests using pymox. When I add a new test that fails, most of the time a whole lot of others fail as well. How can I prevent that from happening?

For example, I have a simple script for which I have two unit tests:

def test_main_returnsUnknown_ifCalculator_returnsMinus1(self):
    m=mox.Mox()
    m.StubOutWithMock(check_es_insert,"getArgs")
    check_es_insert.getArgs(\
        'Nagios plugin for checking the total number of documents stored in Elasticsearch')\
        .AndReturn({ 'critical' : 7, 'warning' : 5, 'address' : 'myhost:1234', 'file' : '/tmp/bla'})
    ################
    #some other mocking here, not relevant, I think
    ################
    m.ReplayAll()
    #now let's test
    check_es_docs.main()
    #verify and cleanup
    m.UnsetStubs()
    m.VerifyAll()
    m.ResetAll()
def test_main_doesWhatPrintAndExitSays_inNormalConditions(self):
    m=mox.Mox()
    m.StubOutWithMock(check_es_insert,"getArgs")
    check_es_insert.getArgs(\
        'Nagios plugin for checking the total number of documents stored in Elasticsearch')\
        .AndReturn({ 'critical' : 7, 'warning' : 5, 'address' : 'myhost:1234', 'file' : '/tmp/bla'})
    ################
    #some other mocking here, not relevant, I think
    ################
    m.ReplayAll()
    #now let's test
    check_es_docs.main()
    #verify and clean up
    m.UnsetStubs()
    m.VerifyAll()
    m.ResetAll()

Normally, both tests pass, but if I sneak in a typo on my second tests, I get this output when running the tests:

$ ./check_es_docs.test.py
FE
======================================================================
ERROR: test_main_returnsUnknown_ifCalculator_returnsMinus1 (__main__.Main)
If it can't get the current value from ES, print an error message and exit 3
----------------------------------------------------------------------
Traceback (most recent call last):
  File "./check_es_docs.test.py", line 13, in test_main_returnsUnknown_ifCalculator_returnsMinus1
    m.StubOutWithMock(check_es_insert,"getArgs")
  File "/usr/local/lib/python2.7/dist-packages/mox-0.5.3-py2.7.egg/mox.py", line 312, in StubOutWithMock
    raise TypeError('Cannot mock a MockAnything! Did you remember to '
TypeError: Cannot mock a MockAnything! Did you remember to call UnsetStubs in your previous test?

======================================================================
FAIL: test_main_doesWhatPrintAndExitSays_inNormalConditions (__main__.Main)
If getCurrent returns a positive value, main() should print the text and exit with the code Calculator.printandexit() says
----------------------------------------------------------------------
Traceback (most recent call last):
  File "./check_es_docs.test.py", line 69, in test_main_doesWhatPrintAndExitSays_inNormalConditions
    check_es_docs.main()
  File "/home/radu/check_es_docs.py", line 25, in main
    check_es_insert.printer("Total number of documents in Elasticsearch is %d | 'es_docs'=%d;%d;%d;;" % (result,result,cmdline['warning'],cmdline['critical']))
  File "/usr/local/lib/python2.7/dist-packages/mox-0.5.3-py2.7.egg/mox.py", line 765, in __call__
    return mock_method(*params, **named_params)
  File "/usr/local/lib/python2.7/dist-packages/mox-0.5.3-py2.7.egg/mox.py", line 1002, in __call__
    expected_method = self._VerifyMethodCall()
  File "/usr/local/lib/python2.7/dist-packages/mox-0.5.3-py2.7.egg/mox.py", line 1060, in _VerifyMethodCall
    raise UnexpectedMethodCallError(self, expected)
UnexpectedMethodCallError: Unexpected method call.  unexpected:-  expected:+
- printer.__call__("Total number of documents in Elasticsearch is 3 | 'es_docs'=3;5;7;;") -> None
?                           -

+ printer.__call__("Total nuber of documents in Elasticsearch is 3 | 'es_docs'=3;5;7;;") -> None

----------------------------------------------------------------------
Ran 2 tests in 0.002s

FAILED (failures=1, errors=1)

The first test should have passed with no error, since it wasn't changed a bit. check_es_insert.getArgs() shouldn't be a MockAnything instance, and I didn't forget to call UnsetStubs. I've searched quite a lot and I didn't find other people with the same problem. So I guess I'm missing something pretty obvious...

Additional info:

• check_es_docs is the script I'm testing
• check_es_insert is another script from which I'm importing a lot of stuff
• I've tried putting UnsetStubs() after VerifyAll() with the same results
• I've tried initializing the mox.Mox() object from the SetUp method, and also putting the cleanup stuff in TearDown, with the same results

Answer 1

I would recommend putting all of your tests into test classes that extend TestCase and then add in an UnsetStubs in the tearDown method:

from unittest import TestCase
import mox

class MyTestCasee(TestCase):
  def __init__(self, testCaseName):
    self.m = mox.Mox()
    TestCase.__init__(self, testCaseName)

  def tearDown(self):
    self.m.UnsetStubs()


def test_main_returnsUnknown_ifCalculator_returnsMinus1(self):
  self.m.StubOutWithMock(check_es_insert,"getArgs")
  check_es_insert.getArgs(\
    'Nagios plugin for checking the total number of documents stored in Elasticsearch')\
    .AndReturn({ 'critical' : 7, 'warning' : 5, 'address' : 'myhost:1234', 'file' : '/tmp/bla'})
  ################
  #some other mocking here, not relevant, I think
  ################
  self.m.ReplayAll()
  #now let's test
  check_es_docs.main()
  #verify and cleanup
  self.m.VerifyAll()

def test_main_doesWhatPrintAndExitSays_inNormalConditions(self):
  self.m.StubOutWithMock(check_es_insert,"getArgs")
  check_es_insert.getArgs(\
      'Nagios plugin for checking the total number of documents stored in Elasticsearch')\
      .AndReturn({ 'critical' : 7, 'warning' : 5, 'address' : 'myhost:1234', 'file' : '/tmp/bla'})
  ################
  #some other mocking here, not relevant, I think
  ################
  self.m.ReplayAll()
  #now let's test
  check_es_docs.main()
  #verify and clean up
  self.m.VerifyAll()
  self.m.ResetAll()

Answer 2

You can also use mox.MoxTestBase, which sets up self.mox and calls VerifyAll() on tearDown.

class ClassTestTest(mox.MoxTestBase):
  def test():
    m = self.mox.CreateMockAnything()

    m.something()
    self.mox.ReplayAll()
    m.something() # If this line is removed the test will fail