How would you test DFS Cycle Detection (Directed Graph)?

Answers use simple, clear English.

Quick interview answer

Test DFS Cycle Detection (Directed Graph) with unit checks for the happy path, integration tests for real I/O boundaries, and load/chaos checks so regressions show up before prod. Core idea: Mitigate first, then root-cause. Check symptoms against: Using two-color visited only (misses cross edges in undirected); forgetting disconnected components..

Detailed answer

Interview answer for testing DFS Cycle Detection (Directed Graph): 1) Unit: isolate the pure logic behind DFS Cycle Detection (Directed Graph) with deterministic fixtures. 2) Integration: exercise real timers/I/O/network boundaries the way production does. 3) Load & soak: prove the event path still meets SLOs under concurrency. 4) Failure injection: break dependencies and assert recovery/backpressure. Best practices to include: Loop all nodes as DFS roots; explain gray = active recursion path. Call out mistakes: Using two-color visited only (misses cross edges in undirected); forgetting disconnected components. Parent context: Mitigate first, then root-cause. Check symptoms against: Using two-color visited only (misses cross edges in undirected); forgetting disconnected components..

Full explanation

Interviewers want a test strategy, not “I would write tests.” Tie each layer back to how DFS Cycle Detection (Directed Graph) fails: correctness, latency, and starvation. Three-color DFS: white=unvisited, gray=in current stack, black=done. Back edge to gray node ⇒ cycle. Works for dependency graphs and course prerequisites.

Follow-up questions

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Parent context — DFS Cycle Detection (Directed Graph)

Mitigate first, then root-cause. Check symptoms against: Using two-color visited only (misses cross edges in undirected); forgetting disconnected components..

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