使用promises并跳过代码时，Mocha测试会超时，为什么？(Mocha test times out when using promises and skips over code, why?)

 我一直试图连续2天运行这个测试，我无法弄清楚它有什么问题： 
 
/*eslint-env mocha */
// var expect = require('chai').expect;
var chai = require('chai');
var chaiAsPromised = require("chai-as-promised");
var expect = chai.expect;
var Promise = require('bluebird');
var Archive = require('../lib/archive');
var path = require('path');
var fs = Promise.promisifyAll(require('fs-extra'));
var globAsync = Promise.promisify(require('glob'));
var tar = require('tar-fs');
var zlib = Promise.promisifyAll(require('zlib'));

chai.use(chaiAsPromised);

describe('Archive', function() {
  var pkg;
  var archive_location;
  var subject;

  beforeEach(function() {
    pkg = {
      name: 'test_0790feebb1',
      recipient_name: 'Test',
      files: {
        letter: '../documents/letters/test/letter.tex',
        resume: '../documents/cover/cover.tex'
      },
      compiled_files: {
        package: '../documents/letters/test/test.pdf'
      }
    };
    archive_location = path.resolve('archives/test_0790feebb1.tar.gz'); 

    subject = new Archive(pkg);
  });

  after(function() {
    return globAsync('archives/test*')
      .each(function(filename) {
        return fs.removeAsync(filename);
      });
  });

  describe('#make', function() {
    it('has the correct directory structure', function() {
      // debugger;
      var tmp_extract_path = path.resolve('test/.tmp');
      var tarPromise = function(data) {
        console.log('tarP'); // never run
        return new Promise(function(reject, resolve) {
          data
            .pipe(zlib.Unzip())
            .pipe(tar.extract(tmp_extract_path))
            .on('error', reject)
            .on('end', resolve);
        });
      };

      var verifyDir = function() {
        console.log('verD'); // never run
        return Promise.all([
            'code',
            'pdf',
            'code/repo',
            'code/documents',
            'code/documents/letters',
            'code/documents/letters/test',
            'code/documents/letters/shared',
            'code/documents/cover',
            'code/documents/letters'
        ].map(function(subpath) {
          return fs.statAsync(path.resolve(tmp_extract_path, subpath));
        }));
      };

      return fs.createReadStreamAsync(archive_location)
        .then(function(data) { return tarPromise(data); })
        .then(function() { return verifyDir(); })
        .then(function(files) {
          console.log(files); // never run
          return expect(true).to.be.true;
        })
        .catch(function(e) { console.log(e); });
    });
  });
});
 
 各种console.log甚至从未执行过，最终测试时间没有任何错误或堆栈跟踪。 
 
 我不知道我做错了什么，承诺现在伤害了我的大脑。 当我使用节点检查器运行代码并取消注释断点时，我可以看到this._runnable._trace值是"done() called multiple times" 。 我不知道这是否是一个实际的错误，也不知道如果这是一个错误，它不会抛出异常。 我无法解释为什么这甚至发生，因为我不再使用任何done()回调和promises，我的测试以function()开头而不是function(done)就像异步测试一样 
 
 有任何想法吗？ 

I have been trying to run this test for 2 days straight now and I can't figure what is wrong with it:
 
/*eslint-env mocha */
// var expect = require('chai').expect;
var chai = require('chai');
var chaiAsPromised = require("chai-as-promised");
var expect = chai.expect;
var Promise = require('bluebird');
var Archive = require('../lib/archive');
var path = require('path');
var fs = Promise.promisifyAll(require('fs-extra'));
var globAsync = Promise.promisify(require('glob'));
var tar = require('tar-fs');
var zlib = Promise.promisifyAll(require('zlib'));

chai.use(chaiAsPromised);

describe('Archive', function() {
  var pkg;
  var archive_location;
  var subject;

  beforeEach(function() {
    pkg = {
      name: 'test_0790feebb1',
      recipient_name: 'Test',
      files: {
        letter: '../documents/letters/test/letter.tex',
        resume: '../documents/cover/cover.tex'
      },
      compiled_files: {
        package: '../documents/letters/test/test.pdf'
      }
    };
    archive_location = path.resolve('archives/test_0790feebb1.tar.gz'); 

    subject = new Archive(pkg);
  });

  after(function() {
    return globAsync('archives/test*')
      .each(function(filename) {
        return fs.removeAsync(filename);
      });
  });

  describe('#make', function() {
    it('has the correct directory structure', function() {
      // debugger;
      var tmp_extract_path = path.resolve('test/.tmp');
      var tarPromise = function(data) {
        console.log('tarP'); // never run
        return new Promise(function(reject, resolve) {
          data
            .pipe(zlib.Unzip())
            .pipe(tar.extract(tmp_extract_path))
            .on('error', reject)
            .on('end', resolve);
        });
      };

      var verifyDir = function() {
        console.log('verD'); // never run
        return Promise.all([
            'code',
            'pdf',
            'code/repo',
            'code/documents',
            'code/documents/letters',
            'code/documents/letters/test',
            'code/documents/letters/shared',
            'code/documents/cover',
            'code/documents/letters'
        ].map(function(subpath) {
          return fs.statAsync(path.resolve(tmp_extract_path, subpath));
        }));
      };

      return fs.createReadStreamAsync(archive_location)
        .then(function(data) { return tarPromise(data); })
        .then(function() { return verifyDir(); })
        .then(function(files) {
          console.log(files); // never run
          return expect(true).to.be.true;
        })
        .catch(function(e) { console.log(e); });
    });
  });
});
 
The various console.log never even get executed and eventually the test times out without any error or stack trace.
 
I have no idea what I am doing wrong and promises hurt my brain now. When I run the code with node inspector and uncomment the breakpoint, I can see that he value of this._runnable._trace is "done() called multiple times". I have no idea if this is an actual error nor why it doesn't throw an exception if that's an error. I can't explain either why this is even happening since I am not using any done() callbacks anymore with promises and that my test starts with function() and not function(done) like an async test would
 
Any ideas?

原文：https://stackoverflow.com/questions/32876127