Testing Strategy and Error Handling Questions

Combines broader testing strategy for systems with a focus on error handling, resilience, and user experience when failures occur. Topics include designing a testing strategy that covers unit tests, integration tests, end to end tests and exploratory testing, applying the testing pyramid, defining error boundaries and recovery paths, graceful degradation and fallback strategies, user feedback and error messaging, fault injection and resilience testing, logging and observability to detect and reproduce errors, and validating error handling behavior across environments and edge cases.

EasyTechnical

0 practiced

Write a small JavaScript function safeParseJSON(jsonString) that returns an object {success: boolean, value: any, error: string|null}. It must not throw, must handle invalid JSON gracefully, and must not allow prototype pollution (i.e., avoid assigning to __proto__ or constructor). Also write one example unit test in Jest for an invalid input.

HardTechnical

0 practiced

Case study: Your product has an SLO of 99.99% successful responses. Define a testing and validation plan (including load, chaos, latency injection) to validate that error handling maintains the error budget at scale. Explain how you'd model error injection and measure whether the application meets the SLO under realistic failure mixes.

MediumTechnical

0 practiced

Describe how you would use feature flags to manage risk for a new error-handling change that alters fallback behavior. Include a test matrix (flag on/off vs environments), rollout plan, key monitoring and rollback criteria, and how tests interact with feature flags.

HardTechnical

0 practiced

Design a deterministic fault-injection harness for a distributed workflow engine that executes multi-step transactions. Describe how you would inject faults deterministically (e.g., at step X, after N ms), how you would capture deterministic traces, and how you'd assert that retry/compensation logic results in a correct final state.

MediumTechnical

0 practiced

Describe how you would automate testing for database migrations. Include steps for schema verification, data-migration validation, rollback verification, and example automated checks that run in CI before a migration is promoted to production.

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