def test_works_for_5(self):
     self.assertEqual([[1], [1, 1], [1, 2, 1], [1, 3, 3, 1], [1, 4, 6, 4, 1]], pascals_triangle.build(5))
 def test_build_with_depth_of_1_is_just_1(self):
     self.assertEqual([[1]], pascals_triangle.build(1))
 def test_build_with_depth_of_2_is_1_and_1_1_and_1_2_1(self):
     self.assertEqual([[1], [1, 1], [1, 2, 1]], pascals_triangle.build(3))