Ember.js: error state workaround

tests__acceptance__errors-test.js

// This is an example of use of `errorStateWorkaround`
import Ember from 'ember';
import { test } from 'qunit';
import moduleForAcceptance from 'my-app/tests/helpers/module-for-acceptance';
import errorStateWorkaround from 'my-app/tests/helpers/error-state-workaround';
 
moduleForAcceptance("Acceptance | errors", {
  beforeEach: function() {
    errorStateWorkaround.setup(err => {
      // Return `true` if `err` is the error
      // we expect, and `false` otherwise
    });
  },
 
  afterEach: function() {
    errorStateWorkaround.teardown();
  },
});

test("Something that lands an error", function(assert) {
  // Do something that would get the user to
  // an error route or substate
 
  andThen(function() {
    // Assert that the error has ocurred as expected
  });
});

tests__helpers__error-state-workaround.js

// Ember annoyingly breaks acceptance tests that involve
// landing on an "error" substate. Until this is solved,
// this workaround helps.
//
// This involves temporariliy overriding Ember.Test.adapter.exception
// to make it not re-raise exceptions related to this
// error substate.
//
// Code is mostly pinched from https://github.com/emberjs/ember.js/issues/12791
// (see comment by @aquamme on May 11, 2016), adapted to
// be reusable.
//
// To use, import this module and call `setup` on the
// test's `beforeEach` hook. Then call `teardown` on
// `afterEach`:
//
//   * `setup`: receives a callback that in turn
//      will receive the raised error. The callback
//      should return a truthy value if the passed error
//      must be ignored, falsy otherwise. Ie: if the
//      passed error is ok and simply part of the error
//      chain expected to lead to the error substate,
//      return true; otherwise return false.
//
//   * `teardown`: doesn't take any arguments.
//
// Note that Ember.Test.adapter.exception will be overriden
// between the calls to `setup` and `teardown`. If you
// do any further override, this code will not work.
//
import Ember from 'ember';
 
export default {
  oldAdapterException: null,
 
  setup(isExpected) {
    this.oldAdapterException = Ember.Test.adapter.exception;
    Ember.Test.adapter.exception = err => {
      if (!isExpected(err)) {
        return this.oldAdapterException(err);
      }
    };
  },
 
  teardown() {
    Ember.Test.adapter.exception = this.oldAdapterException;
  },
};

Discussion around this issue: emberjs/ember.js#12791

Blog post detailing this workaround: https://www.runtastic.com/blog/en/tech/testing-error-states-ember/

Is this workaround still needed with this fix/commit (see last comment in the discussion thread)? emberjs/ember.js#14898