def test_expected_length1():
block = ((1, 4), (3, 5))
length = dtw._distance_matrix_length(block, 6)
assert length == 5
def test_expected_length4():
block = ((0, 6), (0, 6))
length = dtw._distance_matrix_length(block, 6)
assert length == int(6 * (6 - 1) / 2)
