test(coverage): add test coverage

.github/workflows/tests.yml

@@ -0,0 +1,28 @@
+on: ["push", "pull_request"]
+
+name: Test Coveralls
+
+jobs:
+
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+    steps:
+
+    - uses: actions/checkout@v1
+
+    - name: Use Node.js 18.x
+      uses: actions/setup-node@v1
+      with:
+        node-version: 18.x
+
+    - name: yarn install, yarn test:coverage
+      run: |
+        yarn install
+        echo repo_token: ${{ secrets.COVERALLS_REPO_TOKEN }} > .coveralls.yml
+        yarn test:coverage
+
+    - name: Coveralls
+      uses: coverallsapp/github-action@master
+      with:
+        github-token: ${{ secrets.GITHUB_TOKEN }}

package.json

@@ -17,6 +17,7 @@
   ],
   "scripts": {
     "test": "jest",
+    "test:coverage": "jest --coverage && coveralls < coverage/lcov.info",
     "clean": "rimraf dist",
     "build": "yarn clean && tsc --skipLibCheck && yarn build:prod",
     "build:prod": "NODE_ENV=production rollup --config --bundleConfigAsCjs",
@@ -50,6 +51,7 @@
     "@typescript-eslint/eslint-plugin": "^5.56.0",
     "@typescript-eslint/parser": "^5.56.0",
     "commitizen": "^4.3.0",
+    "coveralls": "^3.1.1",
     "eslint": "^8.36.0",
     "eslint-config-airbnb": "^19.0.4",
     "eslint-config-prettier": "^8.8.0",