Add testing action

.github/workflows/tests.yml

@@ -0,0 +1,20 @@
+name: Tests
+
+on: [push, pull_request]
+
+jobs:
+
+  build:
+    name: Run tests
+    runs-on: ubuntu-latest
+
+    steps:
+      # Initialization
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: '16'
+      - run: npm ci
+
+      - name: Run tests
+        run: npm run test-without-building