import unittest
import retworkx
class TestFindCycle(unittest.TestCase):
def setUp(self):
self.graph = retworkx.PyDiGraph()
self.graph.add_nodes_from(list(range(10)))
self.graph.add_edges_from_no_data([
(0, 1),
(3, 0),
(0, 5),
(8, 0),
(1, 2),
(1, 6),
(2, 3),
(3, 4),
(4, 5),
(6, 7),
(7, 8),
(8, 9)])
def test_find_cycle(self):
graph = retworkx.PyDiGraph()
graph.add_nodes_from(list(range(6)))
graph.add_edges_from_no_data([
(0, 1), (0, 3), (0, 5), (1, 2), (2, 3), (3, 4), (4, 5), (4, 0)
])
res = retworkx.digraph_find_cycle(graph, 0)
self.assertEqual([(0, 1), (1, 2), (2, 3), (3, 4), (4, 0)], res)
def test_find_cycle_multiple_roots_same_cycles(self):
res = retworkx.digraph_find_cycle(self.graph, 0)
self.assertEqual(res, [(0, 1), (1, 2), (2, 3), (3, 0)])
res = retworkx.digraph_find_cycle(self.graph, 1)
self.assertEqual(res, [(1, 2), (2, 3), (3, 0), (0, 1)])
res = retworkx.digraph_find_cycle(self.graph, 5)
self.assertEqual(res, [])
def test_find_cycle_disconnected_graphs(self):
self.graph.add_nodes_from(["A", "B", "C"])
self.graph.add_edges_from_no_data([(10, 11), (12, 10), (11, 12)])
res = retworkx.digraph_find_cycle(self.graph, 0)
self.assertEqual(res, [(0, 1), (1, 2), (2, 3), (3, 0)])
res = retworkx.digraph_find_cycle(self.graph, 10)
self.assertEqual(res, [(10, 11), (11, 12), (12, 10)])
def test_invalid_types(self):
graph = retworkx.PyGraph()
with self.assertRaises(TypeError):
retworkx.digraph_find_cycle(graph)
def test_self_loop(self):
self.graph.add_edge(1, 1, None)
res = retworkx.digraph_find_cycle(self.graph, 0)
self.assertEqual([(1, 1)], res)