def test_peeks_at_next_value(self):
"""
Returns the next value in the iterator
"""
pk = PeekableInterface(iter([1, 2, 3, 4]))
result = pk.peek()
self.assertEqual(result, 1)
def test_returns_true_if_has_next(self):
"""
Returns True if there is a next value available in the iterator
"""
pk = PeekableInterface(iter([1, 2, 3, 4]))
result = pk.has_next()
self.assertTrue(result)
def test_returns_false_if_not_next_value(self):
"""
Returns False if there is not a nexr value in the iterator
"""
pk = PeekableInterface(iter([]))
result = pk.has_next()
self.assertFalse(result)
def test_returns_next_value(self):
"""
Returns the next value available in the interator
"""
pk = PeekableInterface(iter([1, 2, 3]))
result = pk.next_value()
self.assertEqual(result, 1)
def test_returns_false_has_next_after_iterating(self):
"""
Returns false from the has_next method after iterating to the end of the iterator
"""
pk = PeekableInterface(iter([1, 2, 3]))
pk.has_next()
one = pk.next_value()
two = pk.next_value()
pk.has_next()
three = pk.next_value()
result = pk.has_next()
self.assertEqual(one, 1)
self.assertEqual(two, 2)
self.assertEqual(three, 3)
self.assertFalse(result)
def test_returns_none_if_not_next_value(self):
"""
Returns None if there is no next value available in the interator
"""
pk = PeekableInterface(iter([1, 2, 3]))
pk.next_value()
pk.next_value()
pk.next_value()
result = pk.next_value()
self.assertIsNone(result)
def test_instantiates(self):
"""
Instantiates a new version of the Peekable Iterface class
"""
pk = PeekableInterface(iter([1, 2, 3, 4]))
self.assertIsInstance(pk, PeekableInterface)