Choose Your Level
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Write Unit Tests for Utility Functions
Write a comprehensive test suite for a complex date-formatting utility.
Integration Testing an API Endpoint
Write tests that verify the database and API routing layers work together.
End-to-End Testing with Playwright
Automate a complex user journey using a headless browser.
Automated Unit & Integration Testing Strategies
Automated testing ensures software code is reliable and regression-free. Engineering managers test candidates on applying the Testing Pyramid (Unit, Integration, E2E), mocking external dependencies (Jest/Vitest mocks, MSW), and targeting meaningful code coverage metrics.
1. Testing Strategy & Coverage Target Spec
Testing document establishing unit vs integration test boundaries, mocking guidelines, and coverage targets.
2. Unit & Integration Test Suite (Jest / Vitest / MSW)
Comprehensive test suite covering domain logic, API handlers, and database interactions.
3. Automated Code Coverage & Benchmark Report
Coverage report verifying 80%+ branch/line coverage with deterministic test execution times.
Frequently Asked Questions (Testing Strategies)
What is the Testing Pyramid?
The Testing Pyramid recommends a foundation of many fast, cheap Unit Tests, a moderate layer of Integration Tests, and a thin top layer of slower E2E Tests.
Why is Mock Service Worker (MSW) preferred for API mocking?
MSW intercepts network requests at the network layer using Service Workers, allowing tests to use real fetch calls without modifying application code.
Why can 100% code coverage be a misleading vanity metric?
100% line coverage only proves code executed during tests, not that assertions verified correctness or edge-case handling.
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