diff options
Diffstat (limited to '.venv/lib/python3.12/site-packages/networkx/algorithms/tests/test_covering.py')
-rw-r--r-- | .venv/lib/python3.12/site-packages/networkx/algorithms/tests/test_covering.py | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/tests/test_covering.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/tests/test_covering.py new file mode 100644 index 00000000..b2f97a86 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/tests/test_covering.py @@ -0,0 +1,85 @@ +import pytest + +import networkx as nx + + +class TestMinEdgeCover: + """Tests for :func:`networkx.algorithms.min_edge_cover`""" + + def test_empty_graph(self): + G = nx.Graph() + assert nx.min_edge_cover(G) == set() + + def test_graph_with_loop(self): + G = nx.Graph() + G.add_edge(0, 0) + assert nx.min_edge_cover(G) == {(0, 0)} + + def test_graph_with_isolated_v(self): + G = nx.Graph() + G.add_node(1) + with pytest.raises( + nx.NetworkXException, + match="Graph has a node with no edge incident on it, so no edge cover exists.", + ): + nx.min_edge_cover(G) + + def test_graph_single_edge(self): + G = nx.Graph([(0, 1)]) + assert nx.min_edge_cover(G) in ({(0, 1)}, {(1, 0)}) + + def test_graph_two_edge_path(self): + G = nx.path_graph(3) + min_cover = nx.min_edge_cover(G) + assert len(min_cover) == 2 + for u, v in G.edges: + assert (u, v) in min_cover or (v, u) in min_cover + + def test_bipartite_explicit(self): + G = nx.Graph() + G.add_nodes_from([1, 2, 3, 4], bipartite=0) + G.add_nodes_from(["a", "b", "c"], bipartite=1) + G.add_edges_from([(1, "a"), (1, "b"), (2, "b"), (2, "c"), (3, "c"), (4, "a")]) + # Use bipartite method by prescribing the algorithm + min_cover = nx.min_edge_cover( + G, nx.algorithms.bipartite.matching.eppstein_matching + ) + assert nx.is_edge_cover(G, min_cover) + assert len(min_cover) == 8 + # Use the default method which is not specialized for bipartite + min_cover2 = nx.min_edge_cover(G) + assert nx.is_edge_cover(G, min_cover2) + assert len(min_cover2) == 4 + + def test_complete_graph_even(self): + G = nx.complete_graph(10) + min_cover = nx.min_edge_cover(G) + assert nx.is_edge_cover(G, min_cover) + assert len(min_cover) == 5 + + def test_complete_graph_odd(self): + G = nx.complete_graph(11) + min_cover = nx.min_edge_cover(G) + assert nx.is_edge_cover(G, min_cover) + assert len(min_cover) == 6 + + +class TestIsEdgeCover: + """Tests for :func:`networkx.algorithms.is_edge_cover`""" + + def test_empty_graph(self): + G = nx.Graph() + assert nx.is_edge_cover(G, set()) + + def test_graph_with_loop(self): + G = nx.Graph() + G.add_edge(1, 1) + assert nx.is_edge_cover(G, {(1, 1)}) + + def test_graph_single_edge(self): + G = nx.Graph() + G.add_edge(0, 1) + assert nx.is_edge_cover(G, {(0, 0), (1, 1)}) + assert nx.is_edge_cover(G, {(0, 1), (1, 0)}) + assert nx.is_edge_cover(G, {(0, 1)}) + assert not nx.is_edge_cover(G, {(0, 0)}) |