test: reimplement unit testing (#229)

* test: add test for `getInputs` function

* ci(test): add `test-package` job

package.json

@@ -4,7 +4,8 @@
   "scripts": {
     "build": "ncc build src/index.ts",
     "format": "prettier --write --cache . !dist !README.md",
-    "lint": "eslint --ignore-path .gitignore ."
+    "lint": "eslint --ignore-path .gitignore .",
+    "test": "jest"
   },
   "dependencies": {
     "@actions/core": "^1.10.1",
@@ -12,12 +13,16 @@
     "@actions/io": "^1.1.3"
   },
   "devDependencies": {
+    "@jest/globals": "^29.7.0",
+    "@types/jest": "^29.5.12",
     "@types/node": "^20.11.24",
     "@typescript-eslint/eslint-plugin": "^7.1.0",
     "@typescript-eslint/parser": "^7.1.1",
     "@vercel/ncc": "^0.38.1",
     "eslint": "^8.57.0",
+    "jest": "^29.7.0",
     "prettier": "^3.2.5",
+    "ts-jest": "^29.1.2",
     "typescript": "^5.3.3"
   },
   "packageManager": "yarn@4.1.1"