Follow-up · depth 11
How would you test CompletableFuture Composition?
How would you test CompletableFuture Composition?
Answers use simple, clear English.
Quick interview answer
Test CompletableFuture Composition 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: Baseline: supplyAsync runs async task; thenApply transforms; thenCompose flattens nested futures; allOf waits for batch. Exceptionally/handle for error paths.
Detailed answer
Interview answer for testing CompletableFuture Composition: 1) Unit: isolate the pure logic behind CompletableFuture Composition 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: Specify executor for IO; use orTimeout/join with timeout in Java 9+. Call out mistakes: Blocking get() on async chain in request thread; lost exceptions without handle. Parent context: Baseline: supplyAsync runs async task; thenApply transforms; thenCompose flattens nested futures; allOf waits for batch. Exceptionally/handle for error paths.
Full explanation
Interviewers want a test strategy, not “I would write tests.” Tie each layer back to how CompletableFuture Composition fails: correctness, latency, and starvation. supplyAsync runs async task; thenApply transforms; thenCompose flattens nested futures; allOf waits for batch. Exceptionally/handle for error paths.
Follow-up questions
Only answered follow-ups are shown — click to open with full answers
Parent context — CompletableFuture Composition
Baseline: supplyAsync runs async task; thenApply transforms; thenCompose flattens nested futures; allOf waits for batch. Exceptionally/handle for error paths.
View full parent question →