116 lines
3.1 KiB
Python
116 lines
3.1 KiB
Python
# test_clique.py - unit tests for the approximation.clique module
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#
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# Copyright 2015 NetworkX developers.
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#
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# This file is part of NetworkX.
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#
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# NetworkX is distributed under a BSD license; see LICENSE.txt for more
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# information.
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"""Unit tests for the :mod:`networkx.algorithms.approximation.clique`
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module.
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"""
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import networkx as nx
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from networkx.algorithms.approximation import max_clique
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from networkx.algorithms.approximation import clique_removal
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from networkx.algorithms.approximation import large_clique_size
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def is_independent_set(G, nodes):
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"""Returns True if and only if `nodes` is a clique in `G`.
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`G` is a NetworkX graph. `nodes` is an iterable of nodes in
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`G`.
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"""
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return G.subgraph(nodes).number_of_edges() == 0
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def is_clique(G, nodes):
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"""Returns True if and only if `nodes` is an independent set
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in `G`.
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`G` is an undirected simple graph. `nodes` is an iterable of
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nodes in `G`.
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"""
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H = G.subgraph(nodes)
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n = len(H)
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return H.number_of_edges() == n * (n - 1) // 2
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class TestCliqueRemoval(object):
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"""Unit tests for the
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:func:`~networkx.algorithms.approximation.clique_removal` function.
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"""
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def test_trivial_graph(self):
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G = nx.trivial_graph()
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independent_set, cliques = clique_removal(G)
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assert is_independent_set(G, independent_set)
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assert all(is_clique(G, clique) for clique in cliques)
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# In fact, we should only have 1-cliques, that is, singleton nodes.
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assert all(len(clique) == 1 for clique in cliques)
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def test_complete_graph(self):
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G = nx.complete_graph(10)
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independent_set, cliques = clique_removal(G)
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assert is_independent_set(G, independent_set)
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assert all(is_clique(G, clique) for clique in cliques)
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def test_barbell_graph(self):
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G = nx.barbell_graph(10, 5)
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independent_set, cliques = clique_removal(G)
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assert is_independent_set(G, independent_set)
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assert all(is_clique(G, clique) for clique in cliques)
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class TestMaxClique(object):
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"""Unit tests for the :func:`networkx.algorithms.approximation.max_clique`
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function.
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"""
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def test_null_graph(self):
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G = nx.null_graph()
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assert len(max_clique(G)) == 0
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def test_complete_graph(self):
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graph = nx.complete_graph(30)
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# this should return the entire graph
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mc = max_clique(graph)
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assert 30 == len(mc)
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def test_maximal_by_cardinality(self):
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"""Tests that the maximal clique is computed according to maximum
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cardinality of the sets.
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For more information, see pull request #1531.
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"""
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G = nx.complete_graph(5)
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G.add_edge(4, 5)
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clique = max_clique(G)
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assert len(clique) > 1
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G = nx.lollipop_graph(30, 2)
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clique = max_clique(G)
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assert len(clique) > 2
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def test_large_clique_size():
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G = nx.complete_graph(9)
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nx.add_cycle(G, [9, 10, 11])
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G.add_edge(8, 9)
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G.add_edge(1, 12)
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G.add_node(13)
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assert large_clique_size(G) == 9
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G.remove_node(5)
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assert large_clique_size(G) == 8
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G.remove_edge(2, 3)
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assert large_clique_size(G) == 7
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