def test_right(self):
expected = 3
zipper = Zipper().insert(1).right
with self.assertRaises(ValueError):
zipper.value
zipper = zipper.insert(expected)
self.assertEqual(zipper.value, expected)
def test_left(self):
expected = 2
zipper = Zipper().insert(1).left
with self.assertRaises(ValueError):
zipper.value
actual = zipper.insert(expected).value
self.assertEqual(actual, expected)
def test_immutability_move_insert(self):
z = Zipper().insert(1).right().insert(4).up().left().insert(2).left().insert(3).left()
z_2 = z.insert(5)
z_3 = z.insert(7)
self.assertIs((z.focus is None), True)
self.assertEqual(z.up().value(), 3)
self.assertNotEqual(z_2.value(), z_3.value())
def test_insert_non_mutating(self):
zipper = Zipper()
zipper.insert(1)
with self.assertRaises(ValueError):
zipper.value