unittest.mock.Mock is not treated as Any in strict mode

[MartinAltmayerTMH]

As far as I know, Mock objects should be treated as Any by type checkers (see e.g. #3611). However, the following code raises type warnings in strict mode.

from unittest.mock import Mock

def test_something():
  item = Mock()
  item.start.assert_not_called()

The errors are

my_test.py
  my_test.py:6:3 - error: Type of "start" is unknown (reportUnknownMemberType)
  my_test.py:6:3 - error: Type of "assert_not_called" is unknown (reportUnknownMemberType)

And if this should be the expected behavior, what is the correct way to work with mock functions like assert_not_called?

Tested with pyright 1.1.331 on the command line.

[erictraut]

The type declaration for Mock indicates that it derives from NonCallableMock which derives from Any.

Currently, when accessing an attribute from a class that derives from Any or , pyright evaluates the type of that attribute as Unknown. This is the intended behavior, but now that you mention it, this behavior seems inconsistent. If you access an attribute from an object that is explicitly declared as Any, pyright evaluates the result as Any. It should arguably do the same if the object is an instance of a class that derives from Any.

c1: Any = 1
reveal_type(c1.foo) # Any

class DerivesFromAny(Any): ...

c2 = DerivesFromAny()
reveal_type(c2.foo) # Unknown

I think it makes sense to change this behavior for consistency. This will be addressed in the next release.

[erictraut]

This is included in pyright 1.1.332, which I just published. It will also be included in a future release of pylance.

[MartinAltmayerTMH]

Thanks for the quick resolution!