test_sqlite3.test_userfunctions redefines test_func_return_too_large_int() method

[vstinner]

Lib/test/test_sqlite3/test_userfunctions.py defines to methods called test_func_return_too_large_int() in the same class, so the first one is never called.

cc @erlend-aasland

Linked PRs

• gh-105557: Remove duplicate sqlite3 test method #105558
• [3.12] gh-105557: Remove duplicate sqlite3 test method (GH-105558) #105561
• [3.11] gh-105557: Remove duplicate sqlite3 test method (GH-105558) #105562

[erlend-aasland]

Oh, that's unfortunate. Thanks for the report, Victor!

[vstinner]

What's unfortunate is that unittest has no metaclass using a prepare method with a custom dict type which detects such bug.

[erlend-aasland]

What's unfortunate is that unittest has no metaclass using a prepare method with a custom dict type which detects such bug.

+1

That would be a useful feature.

[vstinner]

Prototype to detect such bug:

import inspect
import warnings

class MyDict(dict):
    def __init__(self, class_name):
        self.class_name = class_name

    def __setitem__(self, name, value):
        # TestLoader.testMethodPrefix = 'test'
        if name.startswith('test'):
            try:
                old_value = self[name]
            except KeyError:
                pass
            else:
                if inspect.isfunction(old_value):
                    warnings.warn(f"BUG: {self.class_name}.{name}() method redefined", stacklevel=2)
        dict.__setitem__(self, name, value)

class MyMetaClass(type):
    @classmethod
    def __prepare__(metacls, class_name, bases, **kwds):
        return MyDict(class_name)

class TestCase(metaclass=MyMetaClass):
    pass

class Tests(TestCase):
    def __init__(self):
        self.attr = 1
        self.attr = 2

    def test_bug(self):  # first defintion
        pass

    def test_bug(self):  # second definion
        pass


tests = Tests()

Output:

/home/vstinner/python/main/x.py:36: UserWarning: BUG: Tests.test_bug() method redefined
  def test_bug(self):  # second definion

[vstinner]

That would be a useful feature.

I created issue #105560 to track this idea.