def test_eq():
mu = (3, 2, 1)
nu = (2, 1)
u = Vector.base(mu)
v = Vector.base(nu)
w = Vector()
assert w == u - u == v - v
assert u == u + w
assert v == v - w
assert 2 * v + 3 * u == u + v + u + v + u
assert -1 * v + 2 * u == u - v + u
