'Tests for a cut of a single edge.'

def test_single_edge(self):

    G = nx.barbell_graph(3, 0)
    S = {0, 1, 2}
    T = {3, 4, 5}
    assert_equal(nx.cut_size(G, S, T), 1)
    assert_equal(nx.cut_size(G, T, S), 1)
