Testing Strategy and Best Practices

Unit Testing with Jest: #

Minchyn uses Jest for unit testing components, services, and utilities. Tests live in __tests__ directories alongside source files or in a root __tests__ folder. Write tests for critical business logic, utility functions, service methods, and reusable components. Test file naming convention: ComponentName.test.tsx for component tests, serviceName.test.ts for service tests. Use React Native Testing Library for component tests: render, fireEvent, waitFor. Mock external dependencies with jest.mock(). Assert expected behavior, not implementation details. Run tests with npm test, generate coverage with npm test — –coverage. Aim for 80%+ coverage on critical paths.

Component and Integration Testing: #

Test components in isolation by mocking props and context. Verify render output, user interactions, and state changes. Use data-testid for reliable element selection: . Test accessibility: check for proper labels, roles, and keyboard navigation. For integration tests, render connected components with real stores and services. Use MSW (Mock Service Worker) to mock API responses. Test complete user flows: login → navigate → perform action → verify result. Test error scenarios and edge cases. Ensure tests are deterministic and don’t depend on external services.

End-to-End Testing: #

Detox handles E2E testing for React Native apps, running on simulators/emulators. E2E tests verify critical user journeys: signup flow, content creation, purchasing, payments. Tests run against compiled apps in production-like environments. Use device.launchApp(), element(by.id()), tap(), typeText(), expect(element()).toBeVisible(). Run E2E tests before releases to catch regressions. Keep E2E tests focused on happy paths and critical errors–they’re slower than unit tests. Use visual regression testing (Applitools, Percy) for UI consistency. Implement test data factories to generate realistic test data. Run tests in CI/CD pipeline for automated quality gates.