def test_identity_vector_orthogonality_and_parallelism(self):
"""
The zero vector is the only vector that is both orthogonal and
parallel to itself.
"""
v = Vector([0, 0, 0])
self.assertTrue(v.is_orthogonal(v))
self.assertTrue(v.is_parallel(v))
w = Vector([4, 5, 6])
self.assertFalse(w.is_orthogonal(w))
self.assertTrue(w.is_parallel(w))
def test_parallelism(self):
v = Vector([-7.579, -7.88])
w = Vector([22.737, 23.64])
self.assertTrue(v.is_parallel(w))
v = Vector([-2.029, 9.97, 4.172])
w = Vector([-9.231, -6.639, -7.245])
self.assertFalse(v.is_parallel(w))
v = Vector([-2.328, -7.284, -1.214])
w = Vector([-1.821, 1.072, -2.94])
self.assertFalse(v.is_parallel(w))
v = Vector([2.118, 4.827])
w = Vector([0, 0])
self.assertTrue(v.is_parallel(w))
