from nose.tools import *
import networkx as nx
from networkx import *


def test_complement():
    null=null_graph()
    empty1=empty_graph(1)
    empty10=empty_graph(10)
    K3=complete_graph(3)
    K5=complete_graph(5)
    K10=complete_graph(10)
    P2=path_graph(2)
    P3=path_graph(3)
    P5=path_graph(5)
    P10=path_graph(10)
    #complement of the complete graph is empty

    G=complement(K3)
    assert_true(is_isomorphic(G,empty_graph(3)))
    G=complement(K5)
    assert_true(is_isomorphic(G,empty_graph(5)))
    # for any G, G=complement(complement(G))
    P3cc=complement(complement(P3))
    assert_true(is_isomorphic(P3,P3cc))
    nullcc=complement(complement(null))
    assert_true(is_isomorphic(null,nullcc))
    b=bull_graph()
    bcc=complement(complement(b))
    assert_true(is_isomorphic(b,bcc))

def test_complement_2():
    G1=nx.DiGraph()
    G1.add_edge('A','B')
    G1.add_edge('A','C')
    G1.add_edge('A','D')
    G1C=complement(G1)
    assert_equal(sorted(G1C.edges()),
                 [('B', 'A'), ('B', 'C'),
                  ('B', 'D'), ('C', 'A'), ('C', 'B'),
                  ('C', 'D'), ('D', 'A'), ('D', 'B'), ('D', 'C')])