'Tests for creating a directed triangular lattice.'

def test_directed(self):

    G = nx.triangular_lattice_graph(3, 4, create_using=nx.Graph())
    H = nx.triangular_lattice_graph(3, 4, create_using=nx.DiGraph())
    assert_true(H.is_directed())
    for (u, v) in H.edges():
        assert_true((v[1] >= u[1]))
        if (v[1] == u[1]):
            assert_true((v[0] > u[0]))
