def test__init__from_graph(self) -> None:
mg = MultiGraph([(1, 2, 5.0, {
"color": "red"
}), (1, 2, 10.0, {
"color": "black"
}), (3, 4)])
assert mg.weight == 16.0, "multigraph should have weight 16.0"
g = Graph(mg)
assert g.has_edge(
1, 2), "graph should have edge (1, 2) copied from multigraph"
assert (g.get_edge(1, 2)["color"] == "red"
), "edge (1, 2) should have 'color' attribute set to red"
assert g.get_edge(
1, 2).weight == 5.0, "edge (1, 2) should have weight 5.0"
assert g.has_edge(
3, 4), "graph should have edge (3, 4) copied from multigraph"
assert g.edge_count == 2, "graph should have two edges"
assert g.weight == 6.0, "graph should have weight 6.0"
assert g.get_edge(1, 2) is not mg.get_edge( # type: ignore
1, 2), "graph should have deep copies of edges and vertices"
def test_remove_edges_from(self) -> None:
g = Graph([(1, 2), (2, 3), (3, 4)])
assert g.edge_count == 3, "graph should have 3 edges"
g.remove_edges_from([(1, 2), (2, 3)])
assert g.edge_count == 1, "graph should have 1 edge after edge removals"
assert g.has_edge(3, 4)
