def test_clear(self):
t = Tier()
t.extend([Item(id='t1'), Item(id='t2'), Item(id='t3')])
self.assertEqual(len(t), 3)
t.clear()
self.assertEqual(len(t), 0)
self.assertIs(t.get(0), None)
self.assertIs(t.get('t1'), None)
def test_clear(self):
t = Tier()
t.extend([Item(id='t1'), Item(id='t2'), Item(id='t3')])
assert len(t) == 3
t.clear()
assert len(t) == 0
assert t.get(0) is None
assert t.get('t1') is None