[test] installerte pakker, la til tester, la til litt dokumentasjson

.github/workflows/test.yml

@@ -0,0 +1,23 @@
+name: Tests
+
+on:
+  pull_request:
+
+jobs:
+  test:
+    runs-on: self-hosted
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 24
+          cache: npm
+          cache-dependency-path: |
+            package-lock.json
+            backend/package-lock.json
+      - run: npm ci
+      - run: npm ci --prefix backend
+      - name: Frontend tests (components and hooks)
+        run: npm test
+      - name: API tests (GraphQL against in-memory test database)
+        run: npm run test:api

README.md

@@ -54,7 +54,7 @@ Users can mark countries as visited or want to visit. The data is stored in the
 - **Backend**: GraphQL (Node.js/TypeScript)
 - **Database**: PostgreSQL, installed directly on the group's VM
 - **Data**: countries and cities from open datasets (see [Data](#data))
-- **Testing**: Vitest (coming)
+- **Testing**: Vitest and React Testing Library
 - **Linting/formatting**: ESLint and Prettier
 
 ## Architecture and Scalability
@@ -158,10 +158,33 @@ Unless otherwise specified, run these commands from the repository root.
 | `npm run format`       | Format code with Prettier                                              |
 | `npm run format:check` | Check formatting without changing files                                |
 | `npm run preview`      | Preview the production build locally                                   |
+| `npm test`             | Run frontend component and hook tests (Vitest)                         |
+| `npm run test:api`     | Run GraphQL API tests against the test database                        |
 | `npm run fetch-data`   | Fetch and process country and city data into `data/`                   |
 | `npm run db:check`     | Check the database connection (run from `backend/`)                    |
 | `npm run db:seed`      | Populate the database with country and city data (run from `backend/`) |
 
+## Testing
+
+Tests use [Vitest](https://vitest.dev/) and React Testing Library. They use fixed test data and require neither the production database nor the NTNU VPN.
+
+| Command            | What it runs                                                                                             |
+| ------------------ | -------------------------------------------------------------------------------------------------------- |
+| `npm test`         | Component, hook and Apollo cache tests (`src/**/*.test.ts(x)`). Use `npm run test:watch` for watch mode. |
+| `npm run test:api` | GraphQL API tests (`backend/test/`). Same as `npm test` run inside `backend/`.                           |
+
+Before running the API tests for the first time, install the backend dependencies with `cd backend && npm install`.
+
+The API tests run the real resolvers against an in-memory PostgreSQL database ([PGlite](https://pglite.dev/)) that is created and filled with fixed data from `backend/test/testDb.ts` for each run. Nothing needs to be installed or started.
+
+The tests cover search (case-insensitive), filtering, pagination, `totalCount`, loading/error/empty states, debounce (300 ms), "Load more" (offset, counter, last page, retry) and Apollo cache behaviour (separate searches, merged pages without duplicates).
+
+When server-side sorting/filtering ([#27](https://git.ntnu.no/IT2810-H26/T28-Project-2/issues/27)) and search in both countries and cities ([#55](https://git.ntnu.no/IT2810-H26/T28-Project-2/issues/55)) are implemented, extend `backend/test/graphql.test.ts` and `src/lib/apollo.test.ts` with sorting tests on the full result set before pagination, and separate country/city results.
+
+The workflow `.github/workflows/test.yml` runs both test suites on every pull request.
+
+git.ntnu.no has no GitHub-hosted runners, so the workflow runs on a self-hosted runner installed as a service on the group's NTNU VM (`it2810-28.idi.ntnu.no`). The runner is registered under _Settings → Actions → Runners_. If jobs are stuck in "Queued", check that the runner is online there, or run `sudo ./svc.sh status` in the runner folder on the VM.
+
 ## Data
 
 The dataset is generated by `scripts/fetch-data.ts` and saved to `data/`: