def test_sccs(self):
a, b, c, d = ["A"], ["B"], ["C"], ["D"]
a.append(b)
b.append(a)
c.append(d)
d.append(c)
b.append(d)
graph = ObjectGraph([a, b, c, d])
sccs = graph.strongly_connected_components()
self.assertEqual(len(sccs), 2)
self.assertEqual(len(sccs[0]), 2)
self.assertEqual(len(sccs[1]), 2)
# Identify the two sccs.
scc_ab = next(scc for scc in sccs if a in scc)
scc_cd = next(scc for scc in sccs if c in scc)
self.assertIn(a, scc_ab)
self.assertIn(b, scc_ab)
self.assertNotIn(c, scc_ab)
self.assertNotIn(d, scc_ab)
self.assertNotIn(a, scc_cd)
self.assertNotIn(b, scc_cd)
self.assertIn(c, scc_cd)
self.assertIn(d, scc_cd)
# Check that they've got the expected edges.
self.assertEqual(scc_ab.children(a), [b])
self.assertEqual(scc_ab.children(b), [a])
self.assertEqual(scc_cd.children(c), [d])
self.assertEqual(scc_cd.children(d), [c])
def test_long_chain(self):
# The original recursive algorithms failed on long chains.
objects = [[]]
for _ in range(10000):
new_object = []
objects[-1].append(new_object)
objects.append(new_object)
refgraph = ObjectGraph(objects)
sccs = refgraph.strongly_connected_components()
self.assertEqual(len(sccs), len(objects))
def test_analyze_simple_cycle(self):
original_objects = gc.get_objects()
create_cycle()
new_objects = gc.get_objects()
original_ids = set(map(id, original_objects))
new_objects = [obj for obj in new_objects if id(obj) not in original_ids if obj is not original_objects]
refgraph = ObjectGraph(new_objects)
sccs = list(refgraph.strongly_connected_components())
self.assertEqual(len(sccs), 1)
self.assertEqual(len(sccs[0]), 4)