gh-91803: Mock - fix error when using autospec methods with seal #92213
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akulakov
commented
May 3, 2022
•
- Issue: Can't call mocked methods after create_autospec() and seal() #91803
…lakov/cpython into 91803-Fix-seal-with-autospec-methods
| @@ -211,8 +212,6 @@ def ban(self): | |||
| foo.foo() | |||
| with self.assertRaises(AttributeError): | |||
| foo.bar = 1 | |||
| with self.assertRaises(AttributeError): | |||
| foo.bar2() | |||
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I think Nikita is largely on a break from open-source stuff right now FYI
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I feel this is an incorrect assert since bar2 method is present on Foo and shouldn't raise. Removing the assert statement the AttributeError here asserted is for the exception that return_value is not found due to seal which this PR fixes and not that bar2 is not found.
./python Lib/unittest/test/testmock/testsealable.py
..............EE....
======================================================================
ERROR: test_seal_with_autospec (__main__.TestSealable.test_seal_with_autospec) (spec_set=True)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/karthikeyan/stuff/python/cpython/Lib/unittest/test/testmock/testsealable.py", line 215, in test_seal_with_autospec
foo.bar2()
^^^^^^^^^^
File "/home/karthikeyan/stuff/python/cpython/Lib/unittest/mock.py", line 1108, in __call__
return self._mock_call(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/karthikeyan/stuff/python/cpython/Lib/unittest/mock.py", line 1112, in _mock_call
return self._execute_mock_call(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/karthikeyan/stuff/python/cpython/Lib/unittest/mock.py", line 1184, in _execute_mock_call
return self.return_value
^^^^^^^^^^^^^^^^^
File "/home/karthikeyan/stuff/python/cpython/Lib/unittest/mock.py", line 638, in __getattr__
raise AttributeError("Mock object has no attribute %r" % name)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: Mock object has no attribute 'return_value'
======================================================================
ERROR: test_seal_with_autospec (__main__.TestSealable.test_seal_with_autospec) (spec_set=False)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/karthikeyan/stuff/python/cpython/Lib/unittest/test/testmock/testsealable.py", line 215, in test_seal_with_autospec
foo.bar2()
^^^^^^^^^^
File "/home/karthikeyan/stuff/python/cpython/Lib/unittest/mock.py", line 1108, in __call__
return self._mock_call(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/karthikeyan/stuff/python/cpython/Lib/unittest/mock.py", line 1112, in _mock_call
return self._execute_mock_call(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/karthikeyan/stuff/python/cpython/Lib/unittest/mock.py", line 1184, in _execute_mock_call
return self.return_value
^^^^^^^^^^^^^^^^^
File "/home/karthikeyan/stuff/python/cpython/Lib/unittest/mock.py", line 638, in __getattr__
raise AttributeError("Mock object has no attribute %r" % name)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: Mock object has no attribute 'return_value'
----------------------------------------------------------------------
Ran 19 tests in 0.121s
FAILED (errors=2)
Lib/unittest/mock.py
Outdated
| @@ -2731,6 +2731,7 @@ def create_autospec(spec, spec_set=False, instance=False, _parent=None, | |||
| _new_parent=parent, | |||
| **kwargs) | |||
| mock._mock_children[entry] = new | |||
| new.return_value = Mock() | |||
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This could use the child_klass to construct the mock object instead of Mock. This can break code that depended on the return value being an instance of child_klass. Example case as below :
from unittest.mock import create_autospec, seal
class Foo:
def bar(self):
pass
spec = create_autospec(Foo)
print(spec.bar())
print(len(spec.bar()))Python 3.10
python3.10 gh92213.py
<MagicMock name='mock.bar()' id='140499591708000'>
0
With patch
./python gh92213.py
<Mock name='mock.bar()' id='140578691284304'>
Traceback (most recent call last):
File "/home/karthikeyan/stuff/python/cpython/gh92213.py", line 10, in <module>
print(len(spec.bar()))
^^^^^^^^^^^^^^^
TypeError: object of type 'Mock' has no len()
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That makes sense to me, I used Mock originally because I wasn't sure if MagicMock might "evade" seal() if set explicitly, but I tested it and it does not:
class Foo:
x = 1
def foo(self) -> int:
return 0
foo=Foo()
foo = mock.create_autospec(foo)
foo.foo().x
==> AttributeError: mock.foo().x
I've pushed the update to use child_klass()
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@akulakov - rather than just manually testing this, please can you add a test to the test suite to ensure it doesn't change in the future?
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@cjw296 that makes sense, I've expanded the unit test - thanks for noting this.
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@tirkarthi thanks for letting me know, I fixed the conflict. |
Co-authored-by: Karthikeyan Singaravelan <tir.karthi@gmail.com>
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cc: @mariocj89 |
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Updated branch to kick off test again. @tirkarthi - you approved this back in May. Any reason why it was not merged yet? |
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Thanks for reviewing @tirkarthi |