chore: setup unit test CI.

.github/workflows/jest.yml

@@ -0,0 +1,25 @@
+name: Jest unit testing
+
+on: push
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [18.x, 20.x, 22.x]
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v4
+      with:
+        node-version: ${{ matrix.node-version }}
+        cache: 'yarn'
+    - run: yarn
+    - run: yarn test
+    - name: Upload coverage reports to Codecov
+      uses: codecov/codecov-action@v5
+      with:
+        token: ${{ secrets.CODECOV_TOKEN }}

package.json

@@ -14,7 +14,7 @@
   },
   "scripts": {
     "example": "yarn workspace react-native-transformers-example",
-    "test": "jest",
+    "test": "jest --coverage",
     "lint": "eslint . --fix",
     "prepare": "bob build",
     "release": "release-it",