[issue45672] Mutation tests results of typing.py

Oleg Iarygin added the comment: > because this modification does not affect behavior Unfortunately, this one (that I missed by not reading the report thoroughly) makes the framework totally unsuitable for CI. However, looking at such false positives allows to muse about reasons behind desig

[issue45672] Mutation tests results of typing.py

Serhiy Storchaka added the comment: The tests are passed because this modification does not affect behavior, it just makes the code slightly less efficient. Replacing i+1 with i just adds one iteration: b = bases[i] # == self if isinstance(b, _BaseGenericAlias) and b is not self:

[issue45672] Mutation tests results of typing.py

Oleg Iarygin added the comment: > What is the problem actually? I guess, Lib/test/test_typing.py has gaps in test coverage. The report provided by the OP is a list of random modifications that corrupt logic of Lib/typing.py but still pass all test cases. Mutation testing is validation of te

[issue45672] Mutation tests results of typing.py

Serhiy Storchaka added the comment: What is the problem actually? -- nosy: +serhiy.storchaka ___ Python tracker ___ ___ Python-bugs

[issue45672] Mutation tests results of typing.py

Nikita Sobolev added the comment: I can send a PR to have 100% mutation coverage for `typing.py`. I think that a single test can do that. -- ___ Python tracker ___ ___

[issue45672] Mutation tests results of typing.py

New submission from Nikita Sobolev : I've decided to test `typing.py` with `cosmic-ray` mutation testing framework. It identified 3 potential problems. Config: ``` [cosmic-ray] module-path = "Lib/typing.py" timeout = 15.0 excluded-modules = [] test-command = "./python.exe -m test -v test_typi