def test_difference_add(self):
s = CustomSet()
d = CustomSet()
s.add('little')
s.add('mice')
s.add('men')
d.add('little')
d.add('mice')
d.add('woman')
c = d.difference(s)
assert c.contains('woman') == True
def test_difference_fail(self):
s = CustomSet(['animals','love','the','free','land'])
d = CustomSet(['animals','love','the','free', 'land'])
c = d.difference(s)
assert c.contains('land') == False
def test_difference(self):
s = CustomSet(['animals','love','the','free','land'])
d = CustomSet(['animals','love','the','cage'])
c = d.difference(s)
assert c.contains('cage') == True