def test_vertex_count(self) -> None:
g = Graph([(1, 2), (2, 3), (3, 4)])
assert g.vertex_count == 4, "graph should have 4 vertices"
g.add_vertex(5)
assert g.vertex_count == 5, "graph should have 5 vertices"
g.remove_vertex(5)
assert g.vertex_count == 4, "graph should have 4 vertices"
def test_kruskal_optimum_forest_multiple_trees(self) -> None:
g = Graph(test_edges)
g.add_edge("x", "y", weight=22)
g.add_edge("y", "z", weight=20)
g.add_vertex("isolated")
count = 0
total_weight = 0.0
for tree in undirected.kruskal_optimum_forest(g):
count += 1
total_weight += tree.weight
assert count == 3, "there should be 3 trees in the spanning forest"
assert total_weight == 70, "total weight of trees should be 70"
def test_remove_vertex(self) -> None:
g = Graph([(1, 2), (3, 3)])
g.add_vertex(4)
assert g.has_vertex(4), "graph should have vertex 4"
g.remove_vertex(4)
assert not g.has_vertex(
4), "graph should not have vertex 4 after removal"
assert g.has_vertex(3), "graph should have semi-isolated vertex 3"
g.remove_vertex(3)
assert not g.has_vertex(
3), "graph should not have vertex 3 after removal"
with pytest.raises(exception.VertizeeException):
g.remove_vertex(1)
def test_connected_components(self) -> None:
g = Graph([(1, 2), (2, 3), (4, 5), (7, 7)])
g.add_vertex(8)
component_list: List[Component[Vertex, Edge]] = list(
components.connected_components(g))
assert len(component_list) == 4, "graph should have 4 components"
edge_count = sum(
len(list(component.edges())) for component in component_list)
assert edge_count == 4, "components should contain a grand total of 4 edges"
mg: MultiDiGraph = get_example_multidigraph()
scc_list: List[Component[MultiDiVertex, MultiDiEdge]] = list(
components.connected_components(mg))
assert len(
scc_list
) == 4, "multidigraph should have 4 strongly-connected components"
def test_remove_isolated_vertices(self) -> None:
g = Graph([(1, 2), (2, 3), (5, 5)])
g.remove_edge(1, 2, remove_semi_isolated_vertices=False)
g.add_vertex(4)
assert set(g.vertices()) == {g[1], g[2], g[3], g[4], g[5]}
g.remove_isolated_vertices(ignore_self_loops=False)
assert set(g.vertices()) == {
g[2],
g[3],
g[5],
}, "isolated vertices 1 and 4 should have been removed"
g.remove_isolated_vertices(ignore_self_loops=True)
assert set(g.vertices()) == {
g[2], g[3]
}, "semi-isolated vertex 5 should have been removed"
def test_deepcopy(self) -> None:
g = Graph([(1, 2, {"color": "blue"}), (3, 4)])
g.add_vertex(42)
g_copy = g.deepcopy()
assert set(g.vertices()) == set(
g_copy.vertices()), "graph copy should have same vertices"
assert (
g[1] is not g_copy[1]
), "graph copy vertex objects should be distinct from original graph"
assert set(g.edges()) == set(
g_copy.edges()), "graph copy should have same edges"
assert g.get_edge(1, 2) is not g_copy.get_edge(
1, 2
), "graph copy edge objects should be distinct from original graph"
assert (
g.get_edge(1, 2)._attr == g_copy.get_edge(1, 2)._attr
), "graph copy edge object `_attr` dictionary should contain logically equal contents"
assert (
g.get_edge(1, 2)._attr is not g_copy.get_edge(1, 2)._attr
), "graph copy edge object `_attr` dictionary should be distinct from original graph"
def test__getitem__setitem(self) -> None:
g = Graph()
v1: Vertex = g.add_vertex(1)
pairs = [("1", "one"), (2, "two")]
d1: VertexDict[str] = VertexDict(pairs)
assert d1[
v1] == "one", "Dict d1 getitem should work with Vertex object key"
assert d1[1] == "one", "Dict d1 getitem should work with int key"
assert d1["1"] == "one", "Dict d1 getitem should work with int key"
assert d1[
"2"] == "two", "Dict d1 should have item associated with key 2"
d1[2] = "new value"
assert d1[
"2"] == "new value", 'Dict d1 should have "new value" for key 2'
def test_add_vertex(self) -> None:
g = Graph()
g.add_vertex(1)
g.add_vertex("2")
g.add_vertex("v3", color="blue", mass=42)
assert g.has_vertex(1), "graph should have vertex 1"
assert g.has_vertex(2), "graph should have vertex 2"
assert g.has_vertex("v3"), "graph should have vertex v3"
assert g["v3"][
"color"] == "blue", "vertex should have 'color' attribute set to 'blue'"
assert g["v3"][
"mass"] == 42, "vertex should have 'mass' attribute set to 42"