Cache npm install, add tests

.github/workflows/main.yml

@@ -25,13 +25,16 @@ jobs:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
       - uses: actions/checkout@v2
 
-      # - name: Cache NPM dependencies
-      #   uses: actions/cache@v1
-      #   with:
-      #     path: ~/.npm
-      #     key: ${{ runner.OS }}-npm-cache-${{ hashFiles('**/package-lock.json') }}
-      #     restore-keys: |
-      #       ${{ runner.OS }}-npm-cache-
+      - name: Cache NPM dependencies
+        uses: actions/cache@v1
+        with:
+          path: ~/.npm
+          key: ${{ runner.OS }}-npm-cache-${{ hashFiles('**/package-lock.json') }}
+          restore-keys: |
+            ${{ runner.OS }}-npm-cache-
+
+      - name: Test
+        run: npm run test
 
       - name: Install NPM dependencies
         run: npm ci