When using Mocha, test assertion errors are not processed as expected

[n1k0]

I'm trying to use wd-sync with mocha v1.0.1 but it seems test failures are not triggered correctly:

// case_test.js
/* global describe, it */
/* jshint expr:true */

var assert = require('assert');
var wdSync = require('wd-sync');
var client = wdSync.remote();
var browser = client.browser;
var sync = client.sync;

describe("test case", function() {
  it("should pass this test", function(done) {
    this.timeout(10000); // browser start time
    sync(function() {
      browser.init({browserName: 'firefox'});
      browser.get('http://google.com/');
      assert(false);
      browser.quit();
      done();
    });
  });
});

Gives:

$ mocha test/functional/case_test.js

  AssertionError: false == true
    at Object.<anonymous> (/path/to/project/test/functional/case_test.js:16:7)
    at _sync (/path/to/project/node_modules/wd-sync/lib/wd-sync.js:95:21)
    at sync (/path/to/project/node_modules/wd-sync/node_modules/make-sync/lib/make-sync.js:133:14)

As you can see the error is caught and processed by the sync function while it should be by mocha itself.

A working workaround is to patch mocha's it() function:

function _it(description, cb) {
  return it(description, function(done) {
    var context = this;
    sync(function() {
      try {
        cb.call(context, done);
      } catch (err) {
        if (!done)
          throw err;
        browser.quit();
        done.call(context, err);
      }
    });
  });
}

describe("test case", function() {
  _it("should pass this test", function(done) {
    this.timeout(10000); // browser start time
    browser.init({browserName: 'firefox'});
    browser.get('http://google.com/');
    assert(false);
    browser.quit();
    done();
  });
});

which gives:

$ mocha test/functional/case_test.js

  ․

  ✖ 1 of 1 test failed:

  1) test case should pass this test:

  AssertionError: false == true
      at Context.<anonymous> (/Users/niko/Sites/talkilla/test/functional/case_test.js:32:5)
      at Object.<anonymous> (/Users/niko/Sites/talkilla/test/functional/case_test.js:15:12)
      at _sync (/Users/niko/Sites/talkilla/node_modules/wd-sync/lib/wd-sync.js:95:21)
      at sync (/Users/niko/Sites/talkilla/node_modules/wd-sync/node_modules/make-sync/lib/make-sync.js:133:14)

Though I'm finding the hook quite unpleasant and fragile.

[sebv]

The pull request does not seem to solve the issue.

[zah]

What are the problems you are still experiencing?
We've been using the fix for a couple of days now. I'm assuming that the Mocha tests are written using the wrap function as demonstrated in the samples.

[sebv]

Yes the fix works when using wrap but the initial post scope was wider, am wondering if the fix should be moved at the sync level.

[sebv]

No the problem is sync and mocha done callback integration, I don't see a generic way to do it at sync level, the recommended solution is to use wrap, it will hide the done concept totally, and with @zah PR, the exception handling should now work properly.