def test_no_self_loops(self):
g = nx.DiGraph()
g.add_edges_from([('A', 'POAI'), ('POAI', 'A'), ('LIPI', 'POAI'),
('POAI', 'LIPI'), ('POAI', 'B'), ('B', 'POAI'),
('C', 'POAI'), ('POAI', 'C'), ('LIPI', 'A')])
g2 = utils.merge_nodes(g, 'LIPI', ['POAI', 'LIPI'])
self.assertEqual(g2.selfloop_edges(), [])
def test_basic_functionality(self):
g = nx.DiGraph()
g.add_edges_from([('A1', 'A2'), ('A1', 'B'), ('A1', 'C'), ('A2', 'D'),
('A2', 'C'), ('A2', 'E'), ('C', 'A2'), ('E', 'A1'),
('A', 'A1')])
g2 = utils.merge_nodes(g, 'A', ['A1', 'A2', 'A'])
self.assertEqual(g2.number_of_nodes(), 5)
self.assertEqual(g2.edges(), [('A', 'C'), ('A', 'B'), ('A', 'E'),
('A', 'D'), ('C', 'A'), ('E', 'A')])
# Make sure original graph has not been altered.
self.assertEqual(g.number_of_nodes(), 7)
self.assertEqual(g.number_of_edges(), 9)
