[New-bugs-announce] [issue25312] Cryptic error message if incorrect spec is set on a callable mock

[Tzu-ping Chung]

New submission from Tzu-ping Chung:

>>> from unittest import mock
>>> 
>>> class Foo:
...     def __init__(self, val):
...         pass
...     def func(self):
...         pass
... 
>>> class FooMock(mock.Mock):
...     def _get_child_mock(self, **kwargs):
...         return mock.Mock(spec_set=Foo)
... 
>>> mock_foo = FooMock()
>>> mock_foo.func()
<Mock name='mock()' id='4340652632'>
>>> mock_foo.func.mock_calls
[call()]
>>> mock_foo.func.assert_has_calls([mock.call()])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.5/unittest/mock.py", line 824, in assert_has_calls
    ) from cause
AssertionError: Calls not found.
Expected: [call()]
Actual: [call()]


While this code is expected to fail (FooMock.func is set to an incorrect spec), the error message is misleading and does not make any sense.

----------
components: Library (Lib)
messages: 252276
nosy: uranusjr
priority: normal
severity: normal
status: open
title: Cryptic error message if incorrect spec is set on a callable mock
type: behavior
versions: Python 3.4, Python 3.5, Python 3.6

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue25312>
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