def test_get_direction_negative(self):
"""
Test getting the direction between two points.
"""
viz = drawable.Drawable(plt.figure(figsize=(10, 5)))
graph = Graph(viz)
self.assertEqual((-1 / math.sqrt(2), -1 / math.sqrt(2)),
graph._get_direction((0, 0), (-1, -1)))
self.assertEqual((-2 / math.sqrt(5), -1 / math.sqrt(5)),
graph._get_direction((0, 0), (-2, -1)))
self.assertEqual((0, 1), graph._get_direction((-1, -2), (-1, -1)))
self.assertEqual((1 / math.sqrt(2), 1 / math.sqrt(2)),
graph._get_direction((-3, -2), (-2, -1)))
def test_get_direction_not_symmetric(self):
"""
Test that the direction between two points is not symmetric.
"""
viz = drawable.Drawable(plt.figure(figsize=(10, 5)))
graph = Graph(viz)
self.assertEqual((1 / math.sqrt(2), 1 / math.sqrt(2)),
graph._get_direction((-1, -1), (0, 0)))
self.assertEqual((-1 / math.sqrt(2), -1 / math.sqrt(2)),
graph._get_direction((0, 0), (-1, -1)))
self.assertEqual((2 / math.sqrt(5), 1 / math.sqrt(5)),
graph._get_direction((-2, -1), (0, 0)))
self.assertEqual((-2 / math.sqrt(5), -1 / math.sqrt(5)),
graph._get_direction((0, 0), (-2, -1)))
def test_get_direction_same_y_normalized(self):
"""
Test that when getting the direction between two points with the same y-coordinate, the normalized x-direction is returned.
"""
viz = drawable.Drawable(plt.figure(figsize=(10, 5)))
graph = Graph(viz)
self.assertEqual((1, 0), graph._get_direction((0, 0), (2, 0)))
def test_get_direction_same(self):
"""
Test that when getting the direction between the same point, a zero tuple is returned.
"""
viz = drawable.Drawable(plt.figure(figsize=(10, 5)))
graph = Graph(viz)
self.assertEqual((0, 0), graph._get_direction((1, 1), (1, 1)))
