def test_cartesian_vector():
v = CartesianVector()
assert v.x == 0.0
assert v.y == 0.0
assert v.z == 0.0
v = CartesianVector(x=10, y=10, z=10)
assert v.mod == math.sqrt(3 * 10**2)
assert v.spherical_coords == (v.mod, math.atan2(10,
10), math.asin(10 / v.mod))
a = math.atan2(10, 10)
d = math.asin(10 / v.mod)
v = CartesianVector.from_spherical(r=1.0, alpha=a, delta=d)
assert v.mod == 1.0
assert round(v.x, 15) == round(math.cos(d) * math.sin(a), 15)
assert round(v.y, 15) == round(math.cos(d) * math.cos(a), 15)
assert round(v.z, 15) == round(math.sin(d), 15)
r1, a1, d1 = v.spherical_coords
assert r1 == 1.0
assert round(a1, 15) == round(a, 15)
assert round(d1, 15) == round(d, 15)
