write-tests

# Write tests that pass first time Most of the friction in this repository's test suites comes from a handful of specific traps, not from testing being hard. This skill is the list. ## Server tests Server tests need Docker. They run against PostgreSQL through Testcontainers, locally and in CI. ```bash ./gradlew test -x webapp # everything ./gradlew test --tests ExamIntegrationTest -x webapp # one class ./gradlew test --tests ExamIntegrationTest.testGetExamScore # one method ./gradlew test -DincludeTags='ArchitectureTest' -x webapp # architecture only, fast ``` Name tests `*Test.java`. Reuse the module's base class where one exists. Read `reference/server.md` for base class selection, the admin naming rule that forces a different `@ResourceLock`, date comparison, and shared-spy flakiness. The one to know before you start: **in the admin module, naming a test `*IntegrationTest` forces it onto a batch base class carrying a shared `@ResourceLock`.** A test that mutates global state and needs isolation must be named `*Test` and extend `AbstractSpringIntegrationIndependentTest` instead. This is enforced by `src/test/java/de/tum/cit/aet/artemis/admin/architecture/AdminTestArchitectureTest.java`, so getting it wrong fails the architecture gate rather than the test. ## Client tests Vitest, not Jest. Use `vi.spyOn()`, `vi.fn()`, `vi.clearAllMocks()`. ```bash pnpm run vitest # watch pnpm run vitest:run # single run, everything pnpm exec vitest run <path/to/spec.ts> # single file pnpm run vitest:coverage pnpm run test-diff # only specs affected by the diff ``` **`pnpm run vitest:run -- <path>` runs the entire suite.** The path is swallowed. Use `pnpm exec vitest run <path>` for a single file. This wastes a lot of time before people notice. **Vitest is not the type check CI runs.** CI runs a stricter spec `tsc`: ```bash pnpm run compile:tests ``` It enforces member visibility, which Vitest does not. A spec that reaches a private member as `component.privateThing` passes locally and fails in CI. Use bracket access, `component['privateThing']`, and run `compile:tests` before pushing. Read `reference/client.md` for the rest: the monaco stub, zoneless test setup, `model()` versus `input()` plus `output()`, and why template errors need a build rather than a test run. ## Both Keep tests deterministic. Mock external services and WebSockets. CI enforces per-module coverage thresholds, so a new class with no test can fail the build even when nothing is broken. For E2E tests, see `skills/e2e-pr-check/SKILL.md`. Do not add a Playwright test for something a unit or integration test can cover; the E2E suite is the slowest feedback loop in the project.