Issue 31604: unittest.TestLoader().loadTestsFromTestCase(...) fails when adding test cases with the expectedFailure decorator (original) (raw)

How to reproduce:

Run the attached file with Python 2.7 without any modifications. This will produce an error, as described below.
Uncomment line 2 (the decorator @unittest.expectedFailure) and run the file with Python 2.7. This will not produce an error.

Description: Adding the decorator @unittest.expectedFailure to a unittest.TestCase causes the TestLoader().loadTestsFromTestCase(...) to fail with the following output:

=============================================================== $ python2.7 mwe.py Traceback (most recent call last): File "/usr/lib/python2.7/runpy.py", line 174, in _run_module_as_main "main", fname, loader, pkg_name) File "/usr/lib/python2.7/runpy.py", line 72, in _run_code exec code in run_globals File "[...]/mwe.py", line 12, in tests = unittest.TestLoader().loadTestsFromTestCase(TestClassThatFails) File "/usr/lib/python2.7/unittest/loader.py", line 50, in loadTestsFromTestCase if issubclass(testCaseClass, suite.TestSuite): TypeError: issubclass() arg 1 must be a class

The error does only occur when adding the test manually to a test suite. Running unittest.main(), does not produce the error.

I can't reproduce the issue on 3.10, I believe it was fixed by this:

https://github.com/python/cpython/commit/c9b3ef2df06818f055e555c1d23e3ff2d5bf2d74

in particular:

def expectedFailure(func):
```
@functools.wraps(func)
```
```
def wrapper(*args, **kwargs):
```
```
    try:
```
```
        func(*args, **kwargs)
```
```
    except Exception:
```

        raise _ExpectedFailure(sys.exc_info())

```
    raise _UnexpectedSuccess
```
```
return wrapper
```

def expectedFailure(test_item):

test_item.__unittest_expecting_failure__ = True

```
return test_item
```

2.7 won't be fixed, so closing.