Production · FOCUSED GUIDE

Learn Testing.

Choose useful tests and understand mocks, fixtures, and coverage.

YOUR LEARNING PATH

Testing essentials

Start with the essentials or pick the concept you need.

RECOMMENDED NEXTUnit vs integration vs E2E tests?
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01TestingExplore concepts
  1. Unit vs integration vs E2E tests?2 min
  2. What are Jest, React Testing Library and Supertest?2 min
  3. Mock vs stub vs spy vs fixture?2 min
  4. Is 100% coverage enough?2 min

What you will study in Testing

Focused lessons organized by concept. Start with the explanation, trace the examples, and check your recall before moving on.

Testing

Unit tests check a small piece of logic, integration tests verify collaborating components, and E2E tests exercise a complete user or API flow. They catch different classes of failure and have different setup and execution costs. A balanced strategy puts detailed business-rule checks near the unit level and preserves real integration coverage where mocks would hide bugs.

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