Add GitHub action for testing PR to main

.github/workflows/tests.yml

@@ -0,0 +1,38 @@
+name: Tests
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  testing:
+    name: Testing on Node v${{ matrix.node }}
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node: [20]
+    steps:
+      - name: Checking out
+        uses: actions/checkout@v3
+
+      - name: Use Node.js v${{ matrix.node }}
+        uses: actions/setup-node@v3
+        with:
+          node-version: ${{ matrix.node }}
+          cache: "npm"
+
+      - name: Install NPM dependencies
+        run: npm ci
+
+      - name: Check lint
+        run: npm run lint
+
+      - name: Check build
+        run: npm run build
+
+      - name: Run NPM tests
+        run: npm run test