def test_remove(self):
s = ElementTransformSet(transform=lambda x: x*x)
with self.assertRaises(KeyError) as cm:
s.remove(3)
# Make sure that the KeyError carries the original value,
# not the transformed value.
self.assertEqual(cm.exception.args, (3,))
def test_len(self):
s = ElementTransformSet(transform=lambda x: x*x + 1)
self.assertEqual(len(s), 0)
s.add(4)
self.assertEqual(len(s), 1)
s.add(5)
self.assertEqual(len(s), 2)
s.remove(-4)
self.assertEqual(len(s), 1)
s.remove(-5)
self.assertEqual(len(s), 0)
