set up testing infrastructure

.github/workflows/deploy.yaml

@@ -1,19 +1,41 @@
-name: Deploy to Production
+name: Build and Deploy
 
 on:
   push:
     branches:
       - main
+  pull_request:
+    branches: [main]
   workflow_dispatch: {}
 
 concurrency:
   group: "deploy-production"
   cancel-in-progress: true
 
 jobs:
+  test:
+    name: Run tests
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: "20"
+          cache: "npm"
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run tests
+        run: npm test
+
   build:
     name: Build and upload artifact
     runs-on: ubuntu-latest
+    needs: test
 
     steps:
       - uses: actions/checkout@v4
@@ -41,6 +63,8 @@ jobs:
     name: Deploy to server
     runs-on: ubuntu-latest
     needs: build
+    # Only deploy from main branch
+    if: github.ref == 'refs/heads/main'
 
     steps:
       - name: Download build artifact