javascript – Nodeunit test.throws似乎没有捕获错误

我正在尝试为使用Nodeunit在Node.js中编写的模块创建一个测试套件.该模块是一个基本的音乐播放列表,允许添加和删除曲目到播放列表.

var playlist = function(){
    this.__playlist = [];
    this.__count = 0;
};

playlist.prototype = {
    addtrack:function(track){
        if(typeof track !== "object") throw new Error("Track needs to be an oject");
        this.__count++;
        track.id = this.__count;
        this.__playlist.push(track);
        return this.__playlist;
    },removetrack:function(trackid){
        if(typeof trackid !== "number") throw new Error("Pass in a numeric track id");
        var trackFound = false;
        for(var i=0;i<this.__playlist.length;i++){
            var t = this.__playlist[i];
            if(t.id == trackid){
                trackFound = true;
                this.__playlist.splice(i,1);
            }
        }
        if(!trackFound) throw new Error("Track not found in the playlist");
        return this.__playlist
    }
}

exports.playlist = function(){
    return new playlist();
}

你可以看到有地方根据不正确的数据传入错误.

所以这里是我的测试套件.

var pl = require('./playlist');

exports.testPlaylistInit = function(test){
    var playlist = pl.playlist();
    test.equal(typeof playlist,'object');
    test.done();
}

exports.testAddingTracks = function(test){
    var playlist = pl.playlist();
    test.throws(playlist.addtrack(),Error,'Should fail for blank track');
    var track = {
        title: "Golly Sandra",artist: "Eisley",album: "Room Noises"
    };
    tracks = playlist.addtrack(track);
    test.equals(tracks[0],track);
    test.equals(tracks[0].id,1)
    test.done();
}

exports.testRemoveingTracks = function(test){
    var playlist = pl.playlist();
    test.throws(playlist.removetrack('Imma error'),'Show fail for non-numeric track id');
    var track = {
        title: "Golly Sandra",album: "Room Noises"
    };
    playlist.addtrack(track);
    track = {
        title: ".44 Calliber Love Letter",artist: "Alexisonfire",album: "Alexisonfire"
    }
    playlist.addtrack(track);
    test.equals(playlist.removetrack(1)[0],track);
    test.throws(playlist.removetrack(10),'Should fail for non-existant track');
    test.done();
}

在编写测试套件时,我使用test.throws作为假设,基本上只是将代码块包装在一个try-catch语句中,并检查catch对错误块.显然我错了,因为当我使用Nodeunit运行测试时,Node会显示模块抛出的错误消息,而不是测试套件捕获错误.我使用test.throw的情况不正确吗？

解决方法

你对test.throws的使用是不正确的.如果你看看你有什么：

test.throws(
  playlist.removetrack('Imma error'),'Show fail for non-numeric track id'
);

您正在执行playlist.removetrack(‘Imma error’),然后将其结果传递给throws,因此如果有异常,则会在throws被执行之前发生.

你应该做一些更像这样的事情：

test.throws(
  function() {
    playlist.removetrack('Imma error');
  },'Show fail for non-numeric track id'
);

你必须传递一个功能,当执行时,会尝试删除轨道.这样,您的播放列表逻辑实际上由throws函数执行,因此可以自动包装在try / catch块中.

javascript – Nodeunit test.throws似乎没有捕获错误

解决方法

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