https://github.com/python/cpython/commit/72b1004657e60c900e4cd031b2635b587f4... commit: 72b1004657e60c900e4cd031b2635b587f4b280e branch: master author: Karthikeyan Singaravelan <tir.karthi@gmail.com> committer: Chris Withers <chris@withers.org> date: 2020-01-27T06:48:15Z summary: bpo-25597: Ensure wraps' return value is used for magic methods in MagicMock (#16029) files: A Misc/NEWS.d/next/Library/2019-09-12-12-11-05.bpo-25597.mPMzVx.rst M Lib/unittest/mock.py M Lib/unittest/test/testmock/testmock.py diff --git a/Lib/unittest/mock.py b/Lib/unittest/mock.py index beed717522bba..1acafc51df1d6 100644 --- a/Lib/unittest/mock.py +++ b/Lib/unittest/mock.py @@ -2033,6 +2033,12 @@ def __aiter__(): def _set_return_value(mock, method, name): + # If _mock_wraps is present then attach it so that wrapped object + # is used for return value is used when called. + if mock._mock_wraps is not None: + method._mock_wraps = getattr(mock._mock_wraps, name) + return + fixed = _return_values.get(name, DEFAULT) if fixed is not DEFAULT: method.return_value = fixed diff --git a/Lib/unittest/test/testmock/testmock.py b/Lib/unittest/test/testmock/testmock.py index 1329346ae7246..677346725bdd2 100644 --- a/Lib/unittest/test/testmock/testmock.py +++ b/Lib/unittest/test/testmock/testmock.py @@ -715,6 +715,53 @@ def method(self): pass self.assertRaises(StopIteration, mock.method) + def test_magic_method_wraps_dict(self): + data = {'foo': 'bar'} + + wrapped_dict = MagicMock(wraps=data) + self.assertEqual(wrapped_dict.get('foo'), 'bar') + self.assertEqual(wrapped_dict['foo'], 'bar') + self.assertTrue('foo' in wrapped_dict) + + # return_value is non-sentinel and takes precedence over wrapped value. + wrapped_dict.get.return_value = 'return_value' + self.assertEqual(wrapped_dict.get('foo'), 'return_value') + + # return_value is sentinel and hence wrapped value is returned. + wrapped_dict.get.return_value = sentinel.DEFAULT + self.assertEqual(wrapped_dict.get('foo'), 'bar') + + self.assertEqual(wrapped_dict.get('baz'), None) + with self.assertRaises(KeyError): + wrapped_dict['baz'] + self.assertFalse('bar' in wrapped_dict) + + data['baz'] = 'spam' + self.assertEqual(wrapped_dict.get('baz'), 'spam') + self.assertEqual(wrapped_dict['baz'], 'spam') + self.assertTrue('baz' in wrapped_dict) + + del data['baz'] + self.assertEqual(wrapped_dict.get('baz'), None) + + + def test_magic_method_wraps_class(self): + + class Foo: + + def __getitem__(self, index): + return index + + def __custom_method__(self): + return "foo" + + + klass = MagicMock(wraps=Foo) + obj = klass() + self.assertEqual(obj.__getitem__(2), 2) + self.assertEqual(obj.__custom_method__(), "foo") + + def test_exceptional_side_effect(self): mock = Mock(side_effect=AttributeError) self.assertRaises(AttributeError, mock) diff --git a/Misc/NEWS.d/next/Library/2019-09-12-12-11-05.bpo-25597.mPMzVx.rst b/Misc/NEWS.d/next/Library/2019-09-12-12-11-05.bpo-25597.mPMzVx.rst new file mode 100644 index 0000000000000..5ad8c6d90fa03 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2019-09-12-12-11-05.bpo-25597.mPMzVx.rst @@ -0,0 +1,3 @@ +Ensure, if ``wraps`` is supplied to :class:`unittest.mock.MagicMock`, it is used +to calculate return values for the magic methods instead of using the default +return values. Patch by Karthikeyan Singaravelan.