def test_dijkstra_edge_attr_weights(self) -> None:
WEIGHT = "weight_key"
g = DiGraph(
[
("s", "t"),
("s", "y"),
("t", "y"),
("t", "x"),
("x", "z"),
("y", "t"),
("y", "x"),
("y", "z"),
("z", "s"),
("z", "x"),
]
)
g.get_edge("s", "t")[WEIGHT] = 10
g.get_edge("s", "y")[WEIGHT] = 5
g.get_edge("t", "y")[WEIGHT] = 2
g.get_edge("t", "x")[WEIGHT] = 1
g.get_edge("x", "z")[WEIGHT] = 4
g.get_edge("y", "t")[WEIGHT] = 3
g.get_edge("y", "x")[WEIGHT] = 9
g.get_edge("y", "z")[WEIGHT] = 2
g.get_edge("z", "s")[WEIGHT] = 7
g.get_edge("z", "x")[WEIGHT] = 6
path_dict: VertexDict[ShortestPath[DiVertex]] = dijkstra(g, "s", weight=WEIGHT)
assert len(path_dict) == 5, "Shortest path_dict dictionary should have length equal to |V|."
assert path_dict["s"].length == 0, "Length of s path should be 0."
assert path_dict["t"].length == 8, "Length of path s ~> t should be 8."
assert path_dict["x"].length == 9, "Length of path s ~> x should be 9."
assert path_dict["y"].length == 5, "Length of path s ~> y should be 5."
assert path_dict["z"].length == 7, "Length of path s ~> z should be 7."
def test_edges_and_edge_count(self) -> None:
g = DiGraph([(1, 2), (2, 1), (2, 3)])
assert set(g.edges()) == {
g.get_edge(1, 2),
g.get_edge(2, 1),
g.get_edge(2, 3),
}, "edges should be (1, 2), (2, 1), (2, 3)"
assert g.edge_count == 3, "graph should have 3 edges"
def test_dijkstra_edge_weight_filter_function(self) -> None:
COLOR = "color_key"
g = DiGraph(
[
("s", "t", 10),
("s", "y", 5),
("t", "y", 2),
("t", "x", 1),
("x", "z", 4),
("y", "t", 3),
("y", "x", 9),
("y", "z", 2),
("z", "s", 7),
("z", "x", 6),
]
)
g.get_edge("s", "t")[COLOR] = "RED"
g.get_edge("s", "y")[COLOR] = "BLUE"
g.get_edge("t", "y")[COLOR] = "RED"
g.get_edge("t", "x")[COLOR] = "RED"
g.get_edge("x", "z")[COLOR] = "RED"
g.get_edge("y", "t")[COLOR] = "BLUE"
g.get_edge("y", "x")[COLOR] = "RED"
g.get_edge("y", "z")[COLOR] = "BLUE"
g.get_edge("z", "s")[COLOR] = "BLUE"
g.get_edge("z", "x")[COLOR] = "BLUE"
# Exclude blue edges.
def get_weight(v1: V, v2: V, reverse_graph: bool) -> Optional[float]:
graph = v1._parent_graph
if reverse_graph:
edge = graph.get_edge(v2, v1)
edge_str = f"({v2.label}, {v1.label})"
else:
edge = graph.get_edge(v1, v2)
edge_str = f"({v1.label}, {v2.label})"
if edge is None:
raise ValueError(f"graph does not have edge {edge_str}")
if graph.is_multigraph():
assert isinstance(edge, MultiEdgeBase)
has_color = any(c.attr.get(COLOR, "no color") == "BLUE" for c in edge.connections())
if has_color:
return None
return min(c.weight for c in edge.connections())
if cast(Attributes, edge).attr.get(COLOR, "no color attribute") == "BLUE":
return None
return edge.weight
path_dict: VertexDict[ShortestPath[DiVertex]] = dijkstra(g, "s", weight=get_weight)
assert path_dict["s"].length == 0, "Length of s path should be 0."
assert path_dict["t"].length == 10, "Length of path s ~> t should be 10."
assert path_dict["x"].length == 11, "Length of path s ~> x should be 11."
assert path_dict["y"].length == 12, "Length of path s ~> y should be 12."
assert path_dict["z"].length == 15, "Length of path s ~> z should be 15."
def test_get_random_edge(self) -> None:
g = DiGraph([(1, 2), (2, 1), (5, 6)])
cnt: Counter[DiEdge] = collections.Counter()
for _ in range(1000):
rand_edge = g.get_random_edge()
if rand_edge is None:
raise Exception("rand_edge returned None")
cnt[rand_edge] += 1
assert cnt[g.get_edge(
1, 2)] > 270, r"~33% of random samples should be edge (1, 2)"
assert cnt[g.get_edge(
2, 1)] > 270, r"~33% of random samples should be edge (2, 1)"
assert cnt[g.get_edge(
5, 6)] > 270, r"~33% of random samples should be edge (5, 6)"
def test__init__from_graph(self) -> None:
g = Graph([(2, 1, 5.0, {"color": "red"}), (4, 3)])
assert g.weight == 6.0, "graph should have weight 6.0"
dg = DiGraph(g)
assert dg.has_edge(
2, 1), "digraph should have edge (2, 1) copied from graph"
assert (dg.get_edge(2, 1)["color"] == "red"
), "edge (2, 1) should have 'color' attribute set to red"
assert dg.get_edge(
2, 1).weight == 5.0, "edge (2, 1) should have weight 5.0"
assert dg.has_edge(
4, 3), "graph should have edge (4, 3) copied from graph"
assert dg.edge_count == 2, "graph should have two edges"
assert dg.weight == 6.0, "graph should have weight 6.0"
assert dg.get_edge(2, 1) is not g.get_edge( # type: ignore
2, 1), "digraph should have deep copies of edges and vertices"
def test_add_edges_from(self) -> None:
g = DiGraph()
g.add_edges_from([
(1, 2, 4.5, {
"color": "blue",
"mass": 42
}),
(4, 3, 9.5),
(5, 6, {
"color": "red",
"mass": 99
}),
(8, 7),
(7, 8),
])
assert g.edge_count == 5, "digraph should have 5 edges"
assert g.get_edge(
1, 2).weight == 4.5, "edge (1, 2) should have weight 4.5"
assert g.get_edge(
1, 2
)["color"] == "blue", "edge (1, 2) should have 'color' set to 'blue'"
assert g.get_edge(
1, 2)["mass"] == 42, "edge (1, 2) should have 'mass' set to 42"
assert not g.get_edge(4, 3).has_attributes_dict(
), "edge (3, 4) should not have attributes dict"
assert (g.get_edge(5, 6).weight == edge_module.DEFAULT_WEIGHT
), "edge should have default weight"
assert g.get_edge(7, 8) != g.get_edge(
8, 7), "order of vertices should specify different edges"
def test_add_edge(self) -> None:
g = DiGraph()
edge = g.add_edge(2, 1, weight=4.5, color="blue", mass=42)
assert isinstance(edge, DiEdge), "new edge should an DiEdge object"
assert g.get_edge(
2, 1).weight == 4.5, "edge (2, 1) should have weight 4.5"
assert edge[
"color"] == "blue", "edge should have 'color' attribute set to 'blue'"
assert edge[
"mass"] == 42, "edge should have 'mass' attribute set to 42"
edge_dup = g.add_edge(2, 1, weight=1.5, color="red", mass=57)
assert (
edge is edge_dup
), "adding an edge with same vertices as existing edge should return existing edge"
g.add_edge(3, 4)
assert (g.get_edge(3, 4).weight == edge_module.DEFAULT_WEIGHT
), "edge should have default weight"
assert not g.get_edge(3, 4).has_attributes_dict(
), "edge should not have attributes dictionary"
assert not g.has_edge(1, 2), "digraph should not have edge (1, 2)"