Method test_invariant_for_the_in_operator

Lib/test/test_collections.py:2276–2280

(self)

        self.assertEqual(set(Counter(s)), set(s))

    def test_invariant_for_the_in_operator(self):
        c = Counter(a=10, b=-2, c=0)
        for elem in c:
            self.assertTrue(elem in c)
            self.assertIn(elem, c)

    def test_multiset_operations(self):
        # Verify that adding a zero counter will strip zeros and negatives