feat: bootstrap test with jest

Author: zyhou

.babelrc

@@ -1,4 +1,18 @@
 {
+    "env": {
+        "test": {
+            "presets": [
+                [
+                    "@babel/preset-env",
+                    {
+                        "targets": {
+                            "node": "current"
+                        }
+                    }
+                ]
+            ]
+        }
+    },
     "presets": [
         [
             "@babel/preset-env",

.eslintrc.js

@@ -16,6 +16,8 @@ module.exports = {
         'plugin:prettier/recommended',
         'plugin:import/errors',
         'plugin:import/warnings',
+        'plugin:jest/recommended',
+        'plugin:jest/style',
     ],
     rules: {
         'prettier/prettier': 'error',

Makefile

@@ -14,6 +14,12 @@ build: ## Webpack build the project
 	mkdir -p dist
 	npm run build
 
+test: ## Run whole tests
+	npm run test
+
+test-watch: ## Watch whole test suites
+	npm run test:watch
+
 lint: ## lint the code and check coding conventions
 	echo "Running linter..."
 	npm run lint

jest.config.js

@@ -0,0 +1,5 @@
+module.exports = {
+    roots: ['<rootDir>/src'],
+    resetMocks: true,
+    resetModules: true,
+};

package-lock.json

@@ -13,6 +13,8 @@
     "scripts": {
         "start": "webpack-dev-server --config webpack.demo.js --colors --devtool cheap-module-inline-source-map --hot --inline --host=0.0.0.0",
         "build": "webpack",
+        "test": "NODE_ENV=test jest",
+        "test:watch": "NODE_ENV=test jest --watch",
         "lint": "eslint .",
         "format": "prettier --write --check \"**/*.+(js|json|md)\""
     },
@@ -40,14 +42,17 @@
         "@commitlint/cli": "^8.3.5",
         "@commitlint/config-conventional": "^8.3.4",
         "babel-eslint": "^10.0.3",
+        "babel-jest": "^25.1.0",
         "babel-loader": "^8.0.6",
         "eslint": "^6.8.0",
         "eslint-config-prettier": "^6.9.0",
         "eslint-plugin-babel": "^5.3.0",
         "eslint-plugin-import": "^2.20.0",
+        "eslint-plugin-jest": "^23.6.0",
         "eslint-plugin-prettier": "^3.1.2",
         "html-webpack-plugin": "^3.2.0",
         "husky": "^4.2.1",
+        "jest": "^25.1.0",
         "lint-staged": "^10.0.3",
         "prettier": "^1.19.1",
         "webpack": "^4.41.5",

package.json

@@ -0,0 +1,12 @@
+import wait from './wait';
+
+jest.useFakeTimers();
+
+describe('wait', () => {
+    it('should call setTimeout and wait x ms', () => {
+        wait(1000);
+
+        expect(setTimeout).toHaveBeenCalledTimes(1);
+        expect(setTimeout).toHaveBeenLastCalledWith(expect.any(Function), 1000);
+    });
+});