def test_incident_edges_and_loop_edge(self) -> None:
g = MultiGraph()
g.add_vertex(0)
assert not g[0].loop_edge, "vertex 0 should not have a loop edge"
g.add_edges_from([(1, 1), (1, 1), (2, 3), (2, 3)])
assert g[1].incident_edges() == {g.get_edge(
1, 1)}, "vertex 1 should have self loop as incident edge"
assert g[1].loop_edge, "vertex 1 should have a self loop"
assert len(g[2].incident_edges()
) == 1, "vertex 2 should have one incident multiedge"
assert (next(iter(g[2].incident_edges())).multiplicity == 2
), "multiedge (2, 3) should have multiplicity 2"
def test_issubclass_and_isinstance(self) -> None:
g = MultiGraph()
v1 = g.add_vertex(1)
assert isinstance(
v1, vertex_module.VertexBase
), "v1 should be an instance of superclass VertexBase"
assert isinstance(v1,
MultiVertex), "v1 should be a MultiVertex instance"
assert issubclass(MultiVertex, vertex_module.VertexBase
), "MultiVertex should be VertexBase subclass"
def test_degree(self) -> None:
g = MultiGraph()
v0 = g.add_vertex(0)
assert v0.degree == 0, "vertex 0 should have degree 0"
g.add_edge(1, 1)
assert g[1].degree == 2, "vertex with self loop should have degree 2"
g.add_edge(1, 1)
assert g[
1].degree == 4, "vertex with two parallel self loops should have degree 4"
g.add_edge(2, 3)
assert g[2].degree == 1, "vertex 2 should have degree 1"
g.add_edge(2, 3)
assert g[
2].degree == 2, "vertex 2 with two parallel edge connections should have degree 2"
def test_is_vertex_type(self) -> None:
g = Graph()
v: Vertex = g.add_vertex(1)
assert vertex_module.is_vertex_type(
v), "Vertex object should be a VertexType"
g2 = DiGraph()
di_v: DiVertex = g2.add_vertex(1)
assert vertex_module.is_vertex_type(
di_v), "DiVertex object should be a VertexType"
g3 = MultiGraph()
multi_v: MultiVertex = g3.add_vertex(1)
assert vertex_module.is_vertex_type(
multi_v), "MultiVertex object should be a VertexType"
g4 = MultiDiGraph()
multi_di_v: MultiDiVertex = g4.add_vertex(1)
assert vertex_module.is_vertex_type(
multi_di_v), "MultiDiVertex should be a VertexType"
assert vertex_module.is_vertex_type(
10), "int vertex label should be a VertexType"
assert vertex_module.is_vertex_type(
"s"), "str vertex label should be a VertexType"
assert vertex_module.is_vertex_type(("s", {
"color": "blue"
})), "vertex tuple should be a VertexType"
assert not vertex_module.is_vertex_type(
10.99), "float should not be a VertexType"
assert not vertex_module.is_vertex_type(
("s", "t")), "edge tuple should not be a VertexType"
assert not vertex_module.is_vertex_type(
("s", "t",
4.5)), "edge tuple with edge weight should not be a VertexType"
g.add_edge("s", "t")
assert not vertex_module.is_vertex_type(g.get_edge(
"s", "t")), "edge object should not be a VertexType"