add CI test.yml to project

.github/workflows/test.yml

@@ -0,0 +1,43 @@
+name: CI - Test Suite
+
+on:
+  push:
+    branches:
+      - main
+      - phase-1-critical-path
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [18, 20]
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+        # เพื่อให้ทางต้นทางดึง commit ก่อนหน้าได้ (ใช้ในหลายกรณี)
+        with:
+          fetch-depth: 0
+
+      - name: Setup Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run test suite
+        run: npm test
+
+      - name: Report coverage
+        if: success()
+        run: |
+          echo "Test coverage summary:"
+          npm run test:coverage || true