Add unit testing

.babelrc

@@ -0,0 +1,13 @@
+{
+  "presets": [[
+    "@babel/preset-env",
+    {
+      "corejs": "3",
+      "useBuiltIns": "usage"
+    }
+  ]],
+  "plugins": [
+    "@babel/plugin-transform-runtime",
+    "@babel/plugin-proposal-class-properties"
+  ]
+}

.eslintrc.js

@@ -28,4 +28,10 @@ module.exports = {
     'vue/no-unused-vars': 0,
     'vue/html-self-closing': 0,
   },
+  'globals': {
+    'describe': true,
+    'expect': true,
+    'it': true,
+    'test': true,
+  },
 };

package.json

@@ -25,6 +25,9 @@
     "test:sass-lint": "sass-lint 'src/**/*.scss' --verbose --no-exit --config .sasslintrc",
     "test:sass-lint:fix": "sass-lint-auto-fix 'src/**/*.scss'"
   },
+  "jest": {
+    "testRegex": "/test/.*.js?$"
+  },
   "repository": {
     "type": "git",
     "url": "git+https://github.com/digitalocean/nginxconfig.io.git"
@@ -57,12 +60,18 @@
     "vue-select": "^3.10.8"
   },
   "devDependencies": {
+    "@babel/plugin-proposal-class-properties": "^7.10.4",
+    "@babel/plugin-transform-runtime": "^7.11.5",
+    "@babel/preset-env": "^7.11.5",
+    "@babel/runtime": "^7.11.2",
     "@vue/cli-service": "^4.5.7",
     "babel-eslint": "^10.1.0",
     "copyfiles": "^2.4.0",
+    "core-js": "^3.6.5",
     "duplicate-package-checker-webpack-plugin": "^3.0.0",
     "eslint": "^7.11.0",
     "eslint-plugin-vue": "^7.0.1",
+    "jest": "^26.6.3",
     "sass": "^1.27.0",
     "sass-lint": "^1.13.1",
     "sass-lint-auto-fix": "^0.21.2",

test/testBrowserLanguage.js

@@ -0,0 +1,33 @@
+import browserLanguage from '../src/nginxconfig/util/browser_language';
+
+let languages = [];
+
+Object.defineProperty(window.navigator,'languages',{get:function(){
+    return languages;
+}});
+
+Object.defineProperty(window.navigator,'language',{get:function(){
+        return languages[0];
+}});
+
+const setNavigatorLanguges = lang => { languages = lang; };
+
+// eslint-disable-next-line no-global-assign
+Intl = undefined;
+
+describe('#testGetBrowserLanguage', function() {
+    test('#inChina', function() {
+        setNavigatorLanguges(['zh-CN', 'zh', 'en-US', 'en']);
+        expect(browserLanguage()).toEqual('zhCN');
+    });
+
+    test('#inHongKong',function (){
+        setNavigatorLanguges(['zh-TW','zh','en-US','en']);
+        expect(browserLanguage()).toEqual('zhTW');
+    });
+
+    test('#inJapan',function(){
+        setNavigatorLanguges(['ja-JP','ja']);
+        expect(browserLanguage()).toBeFalsy();
+    });
+});