def test_conversions(self):
coordinate_pairs = [
(1, 0, 1, 0),
(0, 1, 1, math.pi / 2),
(-1, 0, 1, math.pi),
(0, -1, 1, -math.pi / 2),
(1, 1, math.sqrt(2), math.pi / 4),
(-1, -1, math.sqrt(2), -math.pi * 3 / 4),
(5, 0, 5, 0),
(0, -5, 5, -math.pi / 2),
(3, 4, 5, math.atan2(4, 3)),
(-3, -4, 5, math.atan2(-4, -3)),
]
for x, y, r, theta in coordinate_pairs:
self.assertSeqAlmostEqual((r, theta), to_polar(x, y))
self.assertSeqAlmostEqual((x, y), to_cartesian(r, theta))
def test_roundtrip(self):
r, theta = 1, 2
self.assertSeqAlmostEqual((r, theta), to_polar(*to_cartesian(r, theta)))
x, y = 5, 2
self.assertSeqAlmostEqual((x, y), to_cartesian(*to_polar(x, y)))