Unable to test Ember.onError after upgrading

[workmanw]

I'm in the process of upgrading to ember 2.10. One of the packages upgraded was ember-cli-qunit which in turn upgrades ember-qunit to 2.0. One problem that I'm faced with is that I am now unable to acceptance test my application's error handling (which is oddly complex and important to test).

The problem is that ember-qunit now providers their own test adapter (See: ember-qunit#234). And the test-loader bundled with ember-cli-qunit just imports it, instanitaties it and set's it as global (See: ember-cli-qunit#134).

Before this upgrade I would just do the following:

let useEmberOnError = false;
Ember.Test.QUnitAdapter.reopen({
  exception(error) {
    if (useEmberOnError) {
      Ember.onerror(error);
      return;
    }

    this._super(...arguments);
  }
});

But now I'm no longer able to monkey patch this. I think I could probably replace the Ember.Test.adapter instance with my own, but this feels brittle. I'm curious what you guys think the "right solution" might be to acceptance test application error handling.

[rwjblue]

I think the best way to do this is:

// tests/qunit-adapter.js
import { QUnitAdapter } from 'ember-qunit';

let useEmberOnError = false;
export default QUnitAdapter.extend({
  exception(error) {
    if (useEmberOnError) {
      Ember.onerror(error);
      return;
    }

    this._super(...arguments);
  }
})

// tests/test-helper.js

/* existing contents */

import QUnitAdapter from './qunit-adapter';
Ember.Test.adapter = QUnitAdapter.create();

[rwjblue]

FWIW, I think ^ was also the best way to do this before ember-qunit@2 too.

[workmanw]

@rwjblue Okay, yea. I think I just needed to reorient my thinking on this. Overriding the adapter in this way feels natural to me. The globals just make things seem wonky sometimes. I think the one catch is you have to be careful when you set the global adapter so that it's done after the test-loader sets it.

It seems like import { QUnitAdapter } from 'ember-qunit'; is probably here to stay for a while? Meaning my extending and replacing of it isn't likely to cause a feature regression.

[kbullaughey]

Now with the start() method for starting tests, which was added in ember-cli-qunit@4, I needed to invoke it as follows for this strategy to work:

start({setupTestAdapter: false});

[thisFunction]

start({setupTestAdapter: false});

Thanks, @kbullaughey! This worked for me when testing backend error responses.