def test_simple_add():
    v1 = Vector([0, 0, 1])
    v2 = Vector([1, 0, 0])
    assert v1 + v2 == Vector([1, 0, 1])

def test_simple_mul():
    v1 = Vector([0, 0, 1])
    assert v1 * 5 == Vector([0, 0, 5])
    assert 5 * v1 == Vector([0, 0, 5])


class Vector(object):
    def __init__(self, components):
        self.components = components

    def _check_lengths_compatible(self, other):
        if len(self.components) != len(other.components):
            raise ValueError("incompatible lenghts")

    def __add__(self, other):
        self._check_lengths_compatible(other)
        result = []
        for a, b in zip(self.components, other.components):
            result.append(a + b)
        return Vector(result)

    def __mul__(self, number):
        result = []
        for a in self.components:
            result.append(a * number)
        return Vector(result)

    __rmul__ = __mul__

    def __eq__(self, other):
        self._check_lengths_compatible(other)
        return self.components == other.components 

    def __ne__(self, other):
        return not (self == other)

    def __repr__(self):
        return "Vector(%s)" % (self.components, )