Add frontend tests, centralize API URL and fix coverage rate translation

.github/workflows/dotnet.yml

@@ -38,7 +38,7 @@ jobs:
         run: dotnet test --no-build --verbosity normal
 
   frontend:
-    name: Frontend (React lint and build)
+    name: Frontend (React lint, test and build)
     runs-on: ubuntu-latest
 
     defaults:
@@ -62,5 +62,8 @@ jobs:
       - name: Lint
         run: npm run lint
 
+      - name: Test
+        run: npm test
+
       - name: Build
         run: npm run build

README.md

@@ -1191,6 +1191,16 @@ The frontend is available at:
 http://localhost:5173
 ```
 
+The API base URL defaults to `http://localhost:5026`. To point the frontend at another API, copy `frontend/.env.example` to `frontend/.env.local` and set `VITE_API_BASE_URL`.
+
+Run the frontend checks:
+
+```bash
+npm run lint
+npm test
+npm run build
+```
+
 ---
 
 # Seed Demo Data
@@ -1268,6 +1278,7 @@ Frontend job:
 
 * installs dependencies with `npm ci`
 * runs ESLint (`npm run lint`)
+* runs the Vitest + React Testing Library tests (`npm test`)
 * builds the production bundle (`npm run build`, including TypeScript type checking)
 
 ---
@@ -1305,6 +1316,19 @@ The solution currently includes 59 unit tests covering:
 * Simulation candidate scoring logic
 * Demo data seeding and reset support
 
+## Frontend tests
+
+The React dashboard has component tests with Vitest, React Testing Library and jsdom. `fetch` is stubbed with fixtures captured from the real API after `POST /api/demo/reset`, so no backend is needed.
+
+They cover:
+
+* Schedule overview rendering and Danish translation of risk indicators (including culture-independent coverage rates)
+* Error page and retry when the API is unavailable
+* Keeping the dashboard visible while refreshing after schedule generation
+* Reloading employee preference profiles after a demo reset
+* Weekly schedule placement per weekday, assigned/unassigned counts and filters
+* Keeping the weekly schedule visible during refresh, plus error and retry
+
 ---
 
 # Example Frontend Demo Flow

frontend/.env.example

@@ -0,0 +1,2 @@
+# Base URL of the ShiftPlanner API (defaults to http://localhost:5026)
+VITE_API_BASE_URL=http://localhost:5026