'Tests the edge boundary of a multdiigraph.'

def test_multidigraph(self):

    edges = [(0, 1), (1, 2), (2, 3), (3, 4), (4, 0)]
    G = nx.MultiDiGraph((edges * 2))
    S = {0, 1}
    boundary = nx.node_boundary(G, S)
    expected = {2}
    assert_equal(boundary, expected)
