'Tests for creating a directed hexagonal lattice.'

def test_directed(self):

    G = nx.hexagonal_lattice_graph(3, 5, create_using=nx.Graph())
    H = nx.hexagonal_lattice_graph(3, 5, create_using=nx.DiGraph())
    assert_true(H.is_directed())
    pos = nx.get_node_attributes(H, 'pos')
    for (u, v) in H.edges():
        assert_true((pos[v][1] >= pos[u][1]))
        if (pos[v][1] == pos[u][1]):
            assert_true((pos[v][0] > pos[u][0]))
