def test_it_provides_a_shorthand_syntax_for_composing_consumers(self):
def consumer(iterable):
for i in iterable:
yield i * 2
l = Latr(xrange(10)) >> consumer
for i in xrange(10):
self.assertEqual(l.next(), i * 2)
def test_values_are_handed_to_consumers_lazily(self):
m = MagicMock('m')
def supplier():
for i in xrange(3):
m()
yield i
def consumer(iterable):
for i in iterable:
yield i * 2
l = Latr(supplier()) >> consumer
self.assertFalse(m.called)
self.assertEqual(l.next(), 0)
self.assertTrue(m.called)
def test_peek_returns_the_same_item_until_next_is_called(self): l = Latr([1, 2, 3]) self.assertEqual(l.peek(), 1) self.assertEqual(l.peek(), 1) self.assertEqual(l.next(), 1) self.assertEqual(l.peek(), 2) self.assertEqual(l.next(), 2) self.assertEqual(l.peek(), 3) self.assertEqual(l.peek(), 3)
def test_has_next_does_not_move_the_iterator(self): l = Latr([1]) l.has_next self.assertEqual(l.next(), 1)
def test_is_empty_does_not_move_the_item_iterator(self): l = Latr([1]) l.is_empty self.assertEqual(l.next(), 1)
def test_it_wraps_an_iterable(self):
l = Latr(xrange(10))
for i in xrange(10):
self.assertEqual(l.next(), i)
