Mock(2.0.0).assert_has_calls() raise AssertionError in two same calls

hello, i use Mock (2.0.0) in python2.7,and found this issue.

Example: test.py

from mock import Mock,call
class BB(object):
    def __init__(self):pass
    def print_b(self):pass
    def print_bb(self,tsk_id):pass

bMock = Mock(return_value=Mock(spec=BB))
bMock().print_bb(20)
bMock().assert_has_calls([call.print_bb(20)])

python test.py Traceback (most recent call last): File “test.py”, line 11, in <module> bMock().assert_has_calls([call.print_bb(20)]) File “/usr/lib/python2.7/site-packages/mock/mock.py”, line 969, in assert_has_calls ), cause) File “/usr/lib/python2.7/site-packages/six.py”, line 718, in raise_from raise value AssertionError: Calls not found. Expected: [call.print_bb(20)] Actual: [call.print_bb(20)]

print expected in mock.py assert_has_calls() [TypeError(‘too many positional arguments’,)]

issue in cpython: http://bugs.python.org/issue26752

[lanzz]

Here is another example that triggers this issue:

import mock
import unittest


class Foo(object):

    def __init__(self, a):
        pass

    def bar(self, a, b):
        return (b, a)


class FooTestCase(unittest.TestCase):

    def test_foo(self):
        mock_class = mock.Mock(spec_set=Foo)
        foo = mock_class(1)
        foo.bar(2, 3)
        mock_class.assert_has_calls(
            [
                mock.call(1),
                mock.call().bar(2, 3),
            ]
        )

Test run output:

$ ./bin/python -m unittest test
F
======================================================================
FAIL: test_foo (test.FooTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "test.py", line 23, in test_foo
    mock.call().bar(2, 3),
  File ".../lib/python2.7/site-packages/mock/mock.py", line 969, in assert_has_calls
    ), cause)
  File ".../lib/python2.7/site-packages/six.py", line 718, in raise_from
    raise value
AssertionError: Calls not found.
Expected: [call(1), call().bar(2, 3)]
Actual: [call(1), call().bar(2, 3)]

----------------------------------------------------------------------
Ran 1 test in 0.005s

FAILED (failures=1)

What I’ve found is that mock_class._call_matcher attempts to bind the bar(2, 3) call to mock_class._spec_signature, but that’s the signature of the Foo class (Foo.__init__(self, a), single positional argument), not that of the Foo.bar method (Foo.bar(self, a, b), two positional arguments), thus it returns TypeError('too many positional arguments') instead. If I drop the spec from the mock, the assertion succeeds, so it is not really a case of calls not matching but obviously a conflict with the spec itself.

[lanzz]

I love it how it took two years and a half to close this issue with “report it upstream instead” 🙄