vitest-unit-patterns

You mock external dependencies like databases and external APIs to isolate API route handlers in Vitest. This ensures tests remain fast and focused solely on business logic without hitting actual external services.

Mocking external API calls in Vitest involves replacing the actual service with a simulated response to isolate utility functions. This approach guarantees test isolation, prevents network latency, and allows you to assert outputs deterministically.

Configuring Vitest for test coverage and path aliases involves adjusting your configuration file to specify coverage thresholds and map import paths. This setup ensures accurate code coverage reporting and resolves module imports correctly during test execution.

Yes, you can test React hooks in Vitest by isolating the hook logic and mocking its dependencies. This pattern allows you to verify the hook's state transitions and effects directly without the overhead of rendering an entire component tree.

Vitest unit tests fail when reaching an external database because they lack proper dependency mocking. You must mock the database calls to isolate the business logic, ensuring the test does not depend on external service availability or state.