节点 assert.throws 未捕获异常 [英] Node assert.throws not catching exception

问题描述

鉴于此代码:

var assert = require('assert');

function boom(){
    throw new Error('BOOM');
}

assert.throws( boom(), Error );

我得到这个输出，节点为 0.4.9:

I get this output, with node 0.4.9:

node.js:134
        throw e; // process.nextTick error, or 'error' event on first tick
        ^
Error: BOOM
    at boom ([EDITED]/assert.throws.test.js:4:9)
    at Object.<anonymous> ([EDITED]/assert.throws.test.js:7:17)
    at Module._compile (module.js:402:26)
    at Object..js (module.js:408:10)
    at Module.load (module.js:334:31)
    at Function._load (module.js:293:12)
    at Array.<anonymous> (module.js:421:10)
    at EventEmitter._tickCallback (node.js:126:26)

对我来说，这意味着发生了未捕获的异常，而不是报告的、捕获的异常.查看文档，我注意到示例看起来更像这样:

This, to me, implies that an uncaught exception has occurred, as opposed to a reported, caught exception. Looking in the docs, I notice that the examples look more like this:

var assert = require('assert');

function boom(){
    throw new Error('BOOM');
}

assert.throws( boom, Error );

但是你如何测试它是否在给定输入的情况下抛出异常?例如:

But how do you test if it throws an exception given a certain input? For example:

var assert = require('assert');

function boom(blowup){
    if(blowup)
        throw new Error('BOOM');
}

assert.throws( boom, Error );

这将失败.我做错了什么，或者除了我之外每个人都知道什么秘密?

This will fail. What am I doing wrong, or what secret does everybody know but me?

推荐答案

示例采用一个函数，而您的示例代码调用一个函数并传递结果.异常发生在断言甚至可以查看它之前.

The examples take a function, while your sample code calls a function and passes the result. The exception happens before the assert even gets to look at it.

将您的代码更改为:

var assert = require('assert');

function boom(){
    throw new Error('BOOM');
}

assert.throws( boom, Error ); // note no parentheses

要传递参数，只需创建另一个函数.毕竟，这是javascript！

To pass parameters, just make another function. After all, this is javascript!

var assert = require('assert');

function boom(blowup){
    if(blowup)
        throw new Error('BOOM');
}

assert.throws( function() { boom(true); }, Error );

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