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unittest loaders should avoid loading test cases that are abstract base classes #120665
Description
Bug report
Bug description:
As reported in Discourse, loading a TestCase-derived subclass that is also an abstract base class like the following:
import unittest
from abc import ABC, abstractmethod
class FooBase(unittest.TestCase, ABC):
@abstractmethod
def test(self): ...
class Foo(FooBase):
def test(self): pass
unittest.main()would currently result in:
TypeError: Can't instantiate abstract class FooBase without an implementation for abstract method 'test'
We should make the unittest loaders avoid loading such test cases and methods from them.
CPython versions tested on:
3.12, CPython main branch
Operating systems tested on:
Linux, Windows
Linked PRs
- gh-120665: make unittest loaders avoid loading test cases that are abstract base classes #120666
- [3.13] gh-120665: make unittest loaders avoid loading test cases that are abstract base classes (GH-120666) #151599
- [3.14] gh-120665: make unittest loaders avoid loading test cases that are abstract base classes (GH-120666) #151600
- [3.15] gh-120665: make unittest loaders avoid loading test cases that are abstract base classes (GH-120666) #151601
Activity
pythongh-120665: make unittest loaders avoid loading test cases that …
pythongh-120665: split the test for loadTestsFromNames into two sub-t…
pythongh-120665: use self.assertRaisesRegex instead of a try block
serhiy-storchaka commentedon Jun 18, 2024
See also previous discussion in #58739.
JonathonReinhart commentedon Jun 15, 2026
Until this issue is resolved, I hope this little snippet helps someone:
gh-120665: make unittest loaders avoid loading test cases that are ab…
[3.14] gh-120665: make unittest loaders avoid loading test cases that…
[3.15] gh-120665: make unittest loaders avoid loading test cases that…
[3.13] gh-120665: make unittest loaders avoid loading test cases that…
pythongh-120665: make unittest loaders avoid loading test cases that …