CODEWITHSUNDEEP
pythonpython-3.xunit-testingpython-unittest
Alan Bagel
Alan Bagel

Reputation: 911

When using Python's unittest to test an class, an strange error occurs

I made the following test case using unittest:

if __name__ == "__main__":
    class TestList(unittest.TestCase):
        def setUp(self):
            self.li = List(["ABC", 5.6, (3, 6)])
    
        def test_append(self):
            self.li.append(1)
            self.assertEqual(self.li, List(["ABC", 5.6, (3, 6), 1]))
    
        def test_insert(self):
            self.li.insert(1, "ABC")

This is my List class (some methods ommited for brevity):

class List(MutableSequence):
    def __init__(self, seq=None):
        self.seq = {} if seq is None else self._dict_from_seq(seq)

    def __getitem__(self, item):
        try:
            return self.seq[item]
        except KeyError:
            raise IndexError("list index out of range") from None

    def __setitem__(self, key, value, *, usage=None):
        if key > max(self.seq.keys()) and usage != "append":
            raise IndexError("list index out of range")
        self.seq[key] = value

    def __delitem__(self, key):
        try:
            del self.seq[key]
        except KeyError:
            raise IndexError("list index out of range") from None

    @classmethod
    def _dict_from_seq(cls, seq):
        return OrderedDict(enumerate(seq))

    def _next_available_slot(self):
        return max(self.seq) + 1

    def append(self, item):
        self.__setitem__(self._next_available_slot(), item, usage="append")

    def insert(self, index, value):
        if index > max(self.seq.keys()):
            raise IndexError("list index out of range")
        self[index] = value

And when I ran unittest.main(), I got the following error:

File "C:\...\AppData\Local\Programs\Python\Python38\lib\unittest\loader.py", line 34, in testFailure
    raise self._exception
  File "C:\...\AppData\Local\Programs\Python\Python38\lib\unittest\loader.py", line 169, in loadTestsFromName
    parent, obj = obj, getattr(obj, part)
AttributeError: module 'fastseq' has no attribute 'TestList'

Why is this happening?

Upvotes: 1

Views: 102

Answers (1)

Alan Bagel
Alan Bagel

Reputation: 911

I solved the problem. Apparently, loader.py could not get the TestList class because __name__ was not __main__. So I just moved the if __name__ == "__main__": line to the spot where I call unittest.main().

Upvotes: 1

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