def test_distinct(self):
buffer = RingBuffer(10)
d = buffer.distinct()
self.assertEqual(len(d), 0)
buffer.append(42)
self.assertEqual(len(buffer.distinct()), 1)
self.assertEqual(buffer.distinct()[0], 42)
buffer.append(42)
self.assertEqual(len(buffer.distinct()), 1)
self.assertEqual(buffer.distinct()[0], 42)
buffer.append(21)
self.assertEqual(len(buffer.distinct()), 2)
self.assertEqual(buffer.distinct()[0], 42)
self.assertEqual(buffer.distinct()[1], 21)
