PT009 changes assertFalse() into assert … is False

[spaceone]

$ cat foo.py
import unittest


class TestFoo(unittest.TestCase):

    def test_foo(self):
        self.assertFalse(None)


unittest.main()
$ ruff --select PT009 --fix foo.py
Found 1 error (1 fixed, 0 remaining).
$ cat foo.py
import unittest


class TestFoo(unittest.TestCase):

    def test_foo(self):
        assert None is False


unittest.main()
$ python3 foo.py
F
======================================================================
FAIL: test_foo (__main__.TestFoo)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "foo.py", line 7, in test_foo
    assert None is False
AssertionError

----------------------------------------------------------------------
Ran 1 test in 0.000s

FAILED (failures=1)

[charliermarsh]

Is this incorrect? :)

[edgarrmondragon]

I guess assertFalse is really checking for falsy values. Maybe the right fix should be

-         self.assertFalse(None)
+         not None

[spaceone]

https://github.com/python/cpython/blob/main/Lib/unittest/case.py#L705-L709
I'll do a PR.

[charliermarsh]

Fixed by #2476.