Lib/tests/list_tests.py is missing type2test in a few methods

[larryhastings]

Bug report

Bug description:

There's almost no documentation for the file Lib/tests/list_tests.py. But I infer from context that it's a suite of tests for list-like objects--not just list, but types.UserList and so on. (I assumed collections.deque would take advantage of this... but it doesn't, huh.)

To use, you define a subclass of list_tests.CommonTest that defines a type2test method which converts an iterable into an object of your type, and run the tests in that object. Then, all the tests in that class use that callable to create the objects they test against.

Or... nearly all. There are (at least) three methods that don't call self.type2test; they only test against list objects. The three methods I found.

• CommonTest.test_getitem_error
• CommonTest.test_setitem_error
• CommonTest.test_constructor_exception_handling

I skimmed over the whole file and only saw those three. Of course I could have easily missed more.

I think someone should update those three tests so they test objects created using self.type2test, and make a more thorough pass over the file making sure there aren't any other missing type2test casts.

CPython versions tested on:

3.13

Operating systems tested on:

Linux

Linked PRs

• gh-138584: Fix missing type2test in Lib/tests/list_tests.py #138586
• gh-138584: Fix missing type2test in Lib/tests/list_tests.py  #138590
• [3.13] gh-138584: Increase test coverage for collections.UserList (GH-138590) #138611
• [3.14] gh-138584: Increase test coverage for collections.UserList (GH-138590) #138612

[picnixz]

Keeping it open until backports land.