前提条件：
1）已安装node.js，且环境变量已配置好；
2）已安装mocha，且环境变量已配置好；
3）已安装chai模块；
4）WebStrom工具已安装好
实现js单元测试详细步骤：
1.打开WebStorm，新建一个HTML5（也可以选择其它）的工程，工程建议最好放置在mocha安装目录下；
2.工程创建好后，如下图包含以下几个目录：
3.在该工程下新建一个文件夹，用来放置自己想要测试脚本，如上图项目中的“testCase”；
4.在“testCase”目录下编写测试代码，并保存至文件test.js，验证代码如：
/**
* Created by 34275 on 2017/7/21.
*/
var expect = require('chai').expect; //依赖于Node
describe('Array', function() {
describe('#indexOf()', function() {
it('should return -1 when the value is not present', function() {
expect([1,2,3].indexOf(4)).equal(-1)
});
it('should return 1 when the value is present', function() {
expect([1,2,3].indexOf(2)).equal(1)
});
it('should return 0 when the value is present', function() {
expect([1,2,3].indexOf(3)).not.equal(1)
});
});
});
5.编辑好代码后在WebStorm上的“Run”下点击“Edit configuration”，进入配置页面：
6.进入配置页面后点击“+”后，选择呈现列表中的“Mocha”，即添加了一个Mocha任务；
7.配置mocha任务的运行参数：
8.配置完毕后，运行上述Mocha任务：
9. 运行完毕后，查看测试结果，下图显示测试均通过：
注：webstorm注册码（测试可用）：
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