'Tests for node contraction in an undirected graph.'

def test_undirected_node_contraction(self):

    G = nx.cycle_graph(4)
    actual = nx.contracted_nodes(G, 0, 1)
    expected = nx.complete_graph(3)
    expected.add_edge(0, 0)
    assert_true(nx.is_isomorphic(actual, expected))
