def test_distances(self):
# (1) test pythagorean triple
vertex_a = Vertex('a')
vertex_b = Vertex('b', 3, 4)
subject = vertex_a.euclidean_distance(vertex_b)
self.assertEqual(subject, 5)
subject = vertex_b.euclidean_distance(vertex_a)
self.assertEqual(subject, 5)
subject = vertex_a.taxicab_distance(vertex_b)
self.assertEqual(subject, 7)
subject = vertex_b.taxicab_distance(vertex_a)
self.assertEqual(subject, 7)
# (2) test linear difference
vertex_a = Vertex('a')
vertex_b = Vertex('b', 0, 10)
subject = vertex_a.euclidean_distance(vertex_b)
self.assertEqual(subject, 10)
subject = vertex_b.euclidean_distance(vertex_a)
self.assertEqual(subject, 10)
subject = vertex_a.taxicab_distance(vertex_b)
self.assertEqual(subject, 10)
subject = vertex_b.taxicab_distance(vertex_a)
self.assertEqual(subject, 10)
# (3) test zero distance
vertex_a = Vertex('a')
vertex_b = Vertex('b')
subject = vertex_a.euclidean_distance(vertex_b)
self.assertEqual(subject, 0)
subject = vertex_b.euclidean_distance(vertex_a)
self.assertEqual(subject, 0)
subject = vertex_a.taxicab_distance(vertex_b)
self.assertEqual(subject, 0)
subject = vertex_b.taxicab_distance(vertex_a)
self.assertEqual(subject, 0)
# (4) test floating point distance
vertex_a = Vertex('a')
vertex_b = Vertex('b', -5, 5)
subject = vertex_a.euclidean_distance(vertex_b)
self.assertAlmostEqual(subject, 5 * math.sqrt(2))
subject = vertex_b.euclidean_distance(vertex_a)
self.assertAlmostEqual(subject, 5 * math.sqrt(2))
subject = vertex_a.taxicab_distance(vertex_b)
self.assertEqual(subject, 10)
subject = vertex_b.taxicab_distance(vertex_a)
self.assertEqual(subject, 10)
