def test_string(self):
inputs = "hey"
outputs = [('h', 'e'), ('e', 'y'), ('y', None)]
self.assertEqual(list(pairwise(inputs)), outputs)
def test_none(self):
inputs = [None, None]
outputs = [(None, None), (None, None)]
self.assertEqual(list(pairwise(inputs)), outputs)
def test_empty(self):
self.assertEqual(list(pairwise([])), [])
def test_one_item(self):
self.assertEqual(list(pairwise([1])), [(1, None)])
def test_three(self):
inputs = [1, 2, 3]
outputs = [(1, 2), (2, 3), (3, None)]
self.assertEqual(list(pairwise(inputs)), outputs)