Add a workflow to validate the generated assets on CI.

.github/workflows/ci.yml

@@ -92,3 +92,36 @@ jobs:
           apt-get install -y libxml2-dev graphviz
       - name: Build and Test
         run: swift test -c release --enable-test-discovery
+
+  validate-assets:
+    runs-on: ubuntu-latest
+
+    name: "Validate Assets"
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v1
+      - name: Setup node.js
+        uses: actions/setup-node@v1
+        with:
+          node-version: 14.x
+      - uses: actions/cache@v2
+        with:
+          path: ~/.npm
+          key: ${{ runner.os }}-node-${{ hashFiles('.node/**/package-lock.json') }}
+          restore-keys: |
+            ${{ runner.os }}-node-
+      - name: Install node dependencies
+        run: |
+          cd .node
+          npm install
+      - name: Test assets
+        run: |
+          cd .node
+          OLD=`cksum ../Resources/all.min.css`
+          npm run build
+          NEW=`cksum ../Resources/all.min.css`
+          if [[ "$OLD" != "$NEW" ]]; then
+            echo "Regenerated assets differ from committed version"
+            exit -1
+          fi

.node/package.json

@@ -5,7 +5,8 @@
     "not dead"
   ],
   "scripts": {
-    "watch": "postcss -w ../Assets/**/*.css -o ../Resources/all.min.css --config ./postcss.config.js"
+    "watch": "postcss -w ../Assets/**/*.css -o ../Resources/all.min.css --config ./postcss.config.js",
+    "build": "postcss ../Assets/**/*.css -o ../Resources/all.min.css --config ./postcss.config.js"
   },
   "dependencies": {
     "cssnano": "^4.1.10",