Jasmine：测试一个setTimeout函数会抛出一个错误 [英] Jasmine: test a setTimeout function throws an error

问题描述

我想测试一个方法的错误处理，该方法使用setTimeout进行调度。错误将在计划部分中抛出，即：

I would like to test the error handling of a method, which schedules work with setTimeout. The error will be thrown in the scheduled part, i.e.:

function sutWithSetTimeout() {
    setTimeout(function () { throw new Error("pang"); }, 1);
}

如何测试是否抛出错误并且消息是否正确？

How do I test that an error is thrown and that it has the correct message?

推荐答案

您需要捕获 setTimeout 中的函数并调用他们使用 expect（function（）{fn（）;}）。toThrow（e）; 。所以你可以窥探 setTimeout 来获得这个函数：

You need to catch the function in the setTimeout and call them using expect(function(){fn();}).toThrow(e);. So you can spy on setTimeout to get the function:

spyOn(window, 'setTimeout');
sutWithSetTimeout();
var fn = window.setTimeout.mostRecentCall.args[0];
expect(fn).toThrow('pang');

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