'Tests for edge contraction in an undirected graph.'

def test_undirected_edge_contraction(self):

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