Testing Strategy and Engineering Quality
Unit, integration, contract, end-to-end, performance, security, and review practices
Test Pyramid and Risk-Based Strategy
Unit tests isolate logic; integration tests validate databases and queues; end-to-end tests cover critical journeys; contract tests protect API compatibility.
How to apply it
Make time and dependencies controllable. Use isolated fixtures. Prioritize tenant isolation, billing, identity, deletion, migrations, and core workflows. Coverage is a signal, not proof of meaningful assertions.
Worked example
Unit-test entitlement rules, integration-test persistence, and end-to-end-test a gated feature journey.
Common mistakes to avoid
Only testing happy paths or relying on coverage percentage as proof of quality.
Practice task
Implement this concept in the capstone. Add one positive test, one negative or failure-path test, and a short note explaining the trade-off you chose.
- Unit tests isolate logic; integration tests validate databases and queues; end-to-end tests cover critical journeys; contract tests protect API compatibility.
- Make time and dependencies controllable.
What is the strongest production practice for Test Pyramid and Risk-Based Strategy?
Contract, End-to-End, and Failure Tests
Contracts validate schemas, status codes, required fields, and error semantics; end-to-end tests validate customer journeys.
How to apply it
Test duplicate webhooks, expired tokens, revoked membership, provider timeouts, queue retries, database conflicts, malformed imports, and billing sandbox flows. Capture request IDs and traces on failure.
Worked example
Submit the same webhook twice and verify a subscription transition occurs once.
Common mistakes to avoid
Using live payments in tests or retrying flaky tests indefinitely.
Practice task
Implement this concept in the capstone. Add one positive test, one negative or failure-path test, and a short note explaining the trade-off you chose.
- Contracts validate schemas, status codes, required fields, and error semantics; end-to-end tests validate customer journeys.
- Test duplicate webhooks, expired tokens, revoked membership, provider timeouts, queue retries, database conflicts, malformed imports, and billing sandbox flows.
What is the strongest production practice for Contract, End-to-End, and Failure Tests?
Performance, Security, and Code Review
Load tests model realistic traffic; stress tests locate limits; soak tests expose degradation. Security checks include dependency scanning, static analysis, secret scanning, and authorization tests.
How to apply it
Define workload, duration, data shape, and success criteria. Run destructive tests in isolated environments. PRs explain problem, risks, tests, rollout, and migrations; reviewers examine authorization, data handling, error paths, observability, and accessibility.
Worked example
Test reading and updating a resource from another tenant and assert no data or side effect leaks.
Common mistakes to avoid
Assuming a green scanner proves security or running destructive tests against customer data.
Practice task
Implement this concept in the capstone. Add one positive test, one negative or failure-path test, and a short note explaining the trade-off you chose.
- Load tests model realistic traffic; stress tests locate limits; soak tests expose degradation. Security checks include dependency scanning, static analysis, secret scanning, and authorization tests.
- Define workload, duration, data shape, and success criteria.
What is the strongest production practice for Performance, Security, and Code Review?