javascript - 如何在 Jasmine 测试中放入调试器？

Question

我正在通过在 Exercism.io 上做练习来提高我的 JavaScript；我目前正在研究http://exercism.io/exercises/javascript/leap/readme .

到目前为止，我已经写了 leap.js像这样:

var Year = function (year) {};

Year.prototype.isLeap = function () {
    return (this.year % 4 === 0 && this.year % 100 !== 0) || this.year % 400 === 0
};

module.exports = Year;

Jasmine 测试，leap.spec.js ，是

var Year = require('./leap');

describe('Leap year', function () {
  it('is not very common', function () {
    var year = new Year(2015);
    expect(year.isLeap()).toBe(false);
  });

  it('is introduced every 4 years to adjust about a day', function () {
    var year = new Year(2016);
    expect(year.isLeap()).toBe(true);
  });

  it('is skipped every 100 years to remove an extra day', function () {
    var year = new Year(1900);
    expect(year.isLeap()).toBe(false);
  });

  it('is reintroduced every 400 years to adjust another day', function () {
    var year = new Year(2000);
    expect(year.isLeap()).toBe(true);
  });

但是，一些测试仍然失败:

Kurts-MacBook-Pro:leap kurtpeek$ jasmine leap.spec.js
Started
.F.F

Failures:
1) Leap year is introduced every 4 years to adjust about a day
  Message:
    Expected false to be true.
  Stack:
    Error: Expected false to be true.
        at UserContext.<anonymous> (/Users/kurtpeek/exercism/javascript/leap/leap.spec.js:11:27)

2) Leap year is reintroduced every 400 years to adjust another day
  Message:
    Expected false to be true.
  Stack:
    Error: Expected false to be true.
        at UserContext.<anonymous> (/Users/kurtpeek/exercism/javascript/leap/leap.spec.js:21:27)

Ran 4 of 8 specs
4 specs, 2 failures
Finished in 0.009 seconds

奇怪的是，如果我复制return使用 this.year 编辑到 Node REPL替换为2016 ，我得到true正如预期的那样:

Kurts-MacBook-Pro:leap kurtpeek$ node
> (2016 % 4 === 0 && 2016 % 100 !== 0) || 2016 % 400 === 0
true

我怀疑正在发生的是this.year不是号码2016 ，但是实例 year的Year这是之前实例化的，因此模表达式没有意义。

但是，为了确认这一点，我想检查 isLeap 范围内的变量。功能。经过一番谷歌搜索后，我尝试安装 jasmine-debug 和 jasmine-node-debug ，但是当我尝试运行其中任何一个时(在 debugger; 语句之前插入 return 语句之后)，我收到以下错误:

Kurts-MacBook-Pro:leap kurtpeek$ jasmine-node-debug
internal/modules/cjs/loader.js:550
    throw err;
    ^

Error: Cannot find module '_debugger'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:548:15)
    at Function.Module._load (internal/modules/cjs/loader.js:475:25)
    at Module.require (internal/modules/cjs/loader.js:598:17)
    at require (internal/modules/cjs/helpers.js:11:18)
    at Object.<anonymous> (/usr/local/lib/node_modules/jasmine-node-debug/node_modules/node-inspector/lib/debugger.js:2:16)
    at Module._compile (internal/modules/cjs/loader.js:654:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:665:10)
    at Module.load (internal/modules/cjs/loader.js:566:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:506:12)
    at Function.Module._load (internal/modules/cjs/loader.js:498:3)

来 self 在https://github.com/angular/protractor/issues/4307读到的内容，此错误与 Node.js 团队将用户迁移到新的 inspect 有关。 API - 基本上，这些包已经过时了。

还有其他方法可以通过Jasmine测试进入调试器吗？

Answer 1

我通过使用 Jasmine CLI 调用的 jasmine.js 文件运行 node --inspect-brk 成功启动了调试器:

Kurts-MacBook-Pro:bin kurtpeek$ node --inspect-brk /usr/local/lib/node_modules/jasmine/bin/jasmine.js ~/exercism/javascript/leap/leap.spec.js
Debugger listening on ws://127.0.0.1:9229/03d10b73-1d60-4db3-be79-850f7ee4d0d6
For help see https://nodejs.org/en/docs/inspector
Debugger attached.
Started

然后，在 Chrome 浏览器中导航至 chrome://inspect 并点击“继续”后，我能够确定 this.year 确实是 未定义:

然后我通过定义 this.year 修复了测试:

var Year = function (year) {
    this.year = year;
};

Year.prototype.isLeap = function () {
    return (this.year % 4 === 0 && this.year % 100 !== 0) || this.year % 400 === 0
};

module.exports = Year;

现在测试通过了:

Kurts-MacBook-Pro:bin kurtpeek$ jasmine ~/exercism/javascript/leap/leap.spec.js
Started
....


Ran 4 of 8 specs
4 specs, 0 failures
Finished in 0.009 seconds