def test_algorithm_valley(self):
backtrack = Backtrack([1, 1, 2, 3, 4, 5])
backtrack._Backtrack__permutation = [3, 1, 1, 2, 4, 5]
self.assertTrue(backtrack.valley())
backtrack._Backtrack__permutation = [3, 1, 2, 1, 4, 5]
self.assertFalse(backtrack.valley())
