Add automated UI tests

.github/workflows/tests.yml

@@ -38,3 +38,32 @@ jobs:
 
       - name: Test
         run: go test -v ./...
+        
+  test-ui:
+    name: Test UI
+    runs-on: ubuntu-latest
+    
+    defaults:
+      run:
+        working-directory: ui
+    
+    strategy:
+      matrix:
+        node-version: [10.x, 14.x]
+
+    steps:
+    - uses: actions/checkout@v2
+      
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v1
+      with:
+        node-version: ${{ matrix.node-version }}
+    
+    - name: Install dependencies
+      run: npm install
+      
+    - name: Build
+      run: npm run build --if-present
+      
+    - name: Test
+      run: npm test