def test_indirect_path_is_shortest(self):
graph = [[0, 1, 3], [math.inf, 0, 1], [math.inf, math.inf, 0]]
expected_distances = [[0, 1, 2], [math.inf, 0, 1],
[math.inf, math.inf, 0]]
self.assertEqual(expected_distances, get_shortest_distances(graph))
def test_path_with_shortcut(self):
graph = [[0, 1, math.inf, math.inf], [1, 0, 1, math.inf],
[math.inf, 2, 0, 1], [math.inf, 1, 5, 0]]
expected_distances = [[0, 1, 2, 3], [1, 0, 1, 2], [3, 2, 0, 1],
[2, 1, 2, 0]]
self.assertEqual(expected_distances, get_shortest_distances(graph))
def test_path_with_two_stops_is_shortest(self):
graph = [[0, 1, 3, 3], [math.inf, 0, 1, 2], [math.inf, math.inf, 0, 1],
[math.inf, math.inf, math.inf, 0]]
expected_distances = [[0, 1, 2, 3], [math.inf, 0, 1, 2],
[math.inf, math.inf, 0, 1],
[math.inf, math.inf, math.inf, 0]]
self.assertEqual(expected_distances, get_shortest_distances(graph))
def test_negative_number(self):
with (self.assertRaisesRegexp(
InvalidGraphError,
'The given graph contains a negative weight.')):
get_shortest_distances([[0, -1], [1, 0]])
def test_graph_with_one_node(self):
self.assertEqual([[0]], get_shortest_distances([[0]]))
def test_not_a_number(self):
with (self.assertRaisesRegexp(
InvalidGraphError,
'The given graph contains a non numeric weight.')):
get_shortest_distances([[0, 'dummy'], [1, 0]])
def test_not_in_quadratic_form(self):
with (self.assertRaisesRegexp(
InvalidGraphError,
'The given graph is not in quadratic form.')):
get_shortest_distances([[0, 2], [1]])
def test_empty_graph(self):
self.assertEqual([], get_shortest_distances([]))
def test_patch_back_to_root(self):
graph = [[0, 1, 3], [1, 0, 1], [4, 2, 0]]
expected_distances = [[0, 1, 2], [1, 0, 1], [3, 2, 0]]
self.assertEqual(expected_distances, get_shortest_distances(graph))
def test_graph_with_two_nodes_and_no_edges(self):
graph = [[0, math.inf], [math.inf, 0]]
expected_distances = [[0, math.inf], [math.inf, 0]]
self.assertEqual(expected_distances, get_shortest_distances(graph))
def test_graph_with_two_nodes_and_a_circle(self):
graph = [[0, 1], [2, 0]]
expected_distances = [[0, 1], [2, 0]]
self.assertEqual(expected_distances, get_shortest_distances(graph))
def test_vertex_to_self_is_not_zero(self):
with self.assertRaisesRegexp(
InvalidGraphError,
'The given graph contains an edge from a vertex to itself that is not 0.'
):
get_shortest_distances([[1]])
