Add unit test GitHub Action (#4)

Author: tushuhei

.github/workflows/unittest.yml

@@ -0,0 +1,41 @@
+name: JavaScript Unit Test
+on:
+  push:
+    paths:
+      - 'src/**'
+  pull_request:
+    paths:
+      - 'src/**'
+permissions:
+  contents: read
+
+jobs:
+  nodejs-unittest:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        node-version: [20, 22]
+
+    steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@0080882f6c36860b6ba35c610c98ce87d4e2f26f # v2.10.2
+        with:
+          egress-policy: audit
+
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+
+      - name: Setup Node ${{ matrix.node-version }}
+        uses: actions/setup-node@39370e3970a6d050c480ffad4ff0ed4d3fdee5af # v4.1.0
+        with:
+          node-version: ${{ matrix.node-version }}
+
+      - name: Install Dependencies
+        run: npm install
+
+      - name: Build
+        run: npm run build
+
+      - name: Run test
+        run: npm test