pytest: Mock returning a mock with specific properties

Question

I found I often use same pattern in tests again and again:

mock_get_data = mock.MagicMock()
mock_get_data.get_data.return_value = "mocked DB data"
mock_db = mock.Mock(spec=DBClass, return_value=mock_get_data)

It would be used for testing (with patching) that type of code:

db_connector = DBClass(settings)
print db_connector.get_data()

Is any way to make that 'double mock' thing shorter?

score 0 · Answer 1 · answered Oct 21 '16 at 14:49

0

You can do like this:

mock_db = mock.Mock(spec=DBClass, return_value=mock.Mock(get_data=lambda:"mocked DB data"))

answered Oct 21 '16 at 14:49

Oleksandr Dashkov

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Is any way to do it without double mock.Mock creation? – George Shuklin Oct 21 '16 at 19:10
You can pass any other object, For example configure class it in the fixtures and pass it like a return_value, but i think that Mock is the more proper way – Oleksandr Dashkov Oct 21 '16 at 20:40

score 0 · Answer 2 · answered Oct 21 '16 at 15:08

You should be able to do this by passing in a dictionary to the constructor, as described in the configure mock section of the docs, instead of configuring it after the MagicMock is created.

I believe the following would achieve the desired result:

mock_db = mock.Mock(spec=DBClass, return_value=mock.MagicMock(**{"get_data.return_value": "mocked DB data"})

pytest: Mock returning a mock with specific properties

2 Answers2