Unit and E2E Testing
Write effective unit tests for individual components and end-to-end tests for complete API flows using Jest and Supertest.
Why Test Your NestJS App?
Writing tests is crucial for building robust applications. It helps ensure your code works as expected and prevents regressions when you make changes.
- Reliability: Confirms features work.
- Refactoring Confidence: Allows changes without fear.
- Documentation: Tests show how code should be used.
In NestJS, we often focus on two main types: Unit Tests and End-to-End (E2E) Tests.
Unit Testing: Isolated Checks
Unit tests focus on the smallest testable parts of your application, called 'units'. Think of individual functions, methods, or classes (like a NestJS service).
The goal is to test each unit in isolation, meaning without its external dependencies (like databases, external APIs, or other services). This makes them fast and easy to pinpoint issues.