edges=[(0, 1, 1), (0, 2, 0), (2, 1, 0)]; start=0
first_discovery_only=[0, 1, 0]; zero_one_bfs=[0, 0, 0]
stale_queue_records=1
graphs=729; start_cases=2187; invalid_inputs=6
PASS: independent enumeration of simple paths, zero cycles and unreachable nodes
