Testing Strategies & Tools

How automated testing works at every layer — from unit tests with Jest and xUnit to end-to-end testing with Playwright and performance profiling.

Unit Tests

Integration

E2E

xUnit/NUnit

Jest & RTL

Playwright

Mocking

TDD

Coverage

Contract Tests

Perf Testing

Test Levels

AAA pattern, test isolation, fakes vs mocks vs stubs.

WebApplicationFactory, in-memory DB, and test server.

Page objects, auto-waiting, assertions, and CI integration.

Tools & Frameworks

Test lifecycle, fixtures, parameterized tests, and assertions.

Component testing, user-event, snapshots, and custom renders.

Moq, NSubstitute, jest.mock — when to mock and when NOT to.

Practices & Quality

Red-Green-Refactor cycle — when TDD helps and when it hinders.

What metrics actually matter and common coverage traps.

Pact, consumer-driven contracts, and schema validation.

k6, JMeter, identifying bottlenecks, and setting baselines.