✅ Setup jest

jest.config.js

@@ -0,0 +1,6 @@
+/** @type {import('ts-jest/dist/types').InitialOptionsTsJest} */
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+  testMatch: ['src/**/*.test.ts'],
+}

package.json

@@ -8,7 +8,8 @@
     "melon": "./dist/index.js"
   },
   "scripts": {
-    "test": "echo \"Error: no test specified\"",
+    "test": "jest",
+    "test:dev": "jest --watch",
     "build": "rm -rf dist/ && tsc && echo \"#!/usr/bin/env node\"|cat - ./dist/index.js > /tmp/out && mv /tmp/out ./dist/index.js && chmod +x ./dist/index.js",
     "format": "prettier . -w",
     "lint": "eslint .",
@@ -51,6 +52,7 @@
   "devDependencies": {
     "@types/cli-progress": "^3.9.2",
     "@types/fs-extra": "^9.0.13",
+    "@types/jest": "^27.0.3",
     "@types/listr": "^0.14.4",
     "@types/node": "^14.14.16",
     "@types/prompts": "^2.0.14",
@@ -65,7 +67,9 @@
     "eslint-plugin-jsx-a11y": "^6.4.1",
     "eslint-plugin-react": "^7.21.5",
     "eslint-plugin-react-hooks": "^1.7.0",
+    "jest": "^27.4.5",
     "prettier": "^2.2.1",
+    "ts-jest": "^27.1.2",
     "typescript": "^4.1.3"
   }
 }