如何为这个函数编写一个测试用例

Question

//定时器功能代码//

Function startTimer (event)
{
var session Timeout= 
setTimeout (function ()
{
Self.postMessage (
{
Message:'show dialog'
};
);
},  event.duration);
}

如何为此编写测试用例？

Answer 1

参考Jest 中提供的定时器模型

https://jestjs.io/docs/timer-mocks

jest.useFakeTimers();
jest.spyOn(global, 'setTimeout');
test('Timer Function', () => {
const startTimer  = require('../startTimer ');
startTimer ();
expect(setTimeout).toHaveBeenCalledTimes(1);
expect(setTimeout).toHaveBeenLastCalledWith(expect.any(Function), event.duration);
});