Add GitHub workflow for integration tests

.github/workflows/integration-tests.yml

@@ -0,0 +1,41 @@
+name: Integration Tests
+
+on:
+  # Run on all pull requests.
+  pull_request:
+  push:
+    branches:
+      - trunk
+
+# Cancels all previous workflow runs for pull requests that have not completed.
+concurrency:
+  # The concurrency group contains the workflow name and the branch name for pull requests
+  # or the commit hash for any other events.
+  group: ${{ github.workflow }}-${{ github.event_name == 'pull_request' && github.head_ref || github.sha }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: WordPress Integration Tests
+    runs-on: ubuntu-24.04
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Use desired version of NodeJS
+        uses: actions/[email protected]
+        with:
+          node-version: 20
+          cache: npm
+
+      - name: Npm install
+        run: |
+          npm ci
+
+      - name: Start up WordPress environment
+        run: |
+          npm run dev:build
+
+      - name: Run Integration tests
+          npm run test:integration