Testing

Things to keep in mind when writing tests for API routes served by Express.

Application Interface

Tests should mainly test the API interface per best practices.

To do this:

• Create an Express app for each test, using the app exported by http.ts, using beforeEach.
• Use @saflib/express's makeUserHeaders to create headers that would otherwise be provided by the identity service via Caddy.
• Use supertest's request to make the request.

Tests should include at least one test for each response code. It does not need to test invalid inputs (one can assume express-openapi-validator will do its job).

Mocking

Tests for Express routes should be integration tests that use the actual database but mock other services, both internal and external.

Mocks should not be owned by the @saflib/express-dependent package, however. Instead, the service client should mock behavior when in a test environment. Express packages should refrain from creating their own mocks and instead contribute to the client package's mocking system per best practices.

When tests want to change mock behaviors, for example to test error responses, they should import mocks provided by those client libraries and use vi.spyOn on the client to incorporate those mocks.