Unit Test Component?

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  classNameBindings: [
    'hasError:error:no-error', 'classes',
  ],

  errors: [],
  includeFieldName: false,
  field: '',

  hasError: Ember.computed('fieldErrors.@each', function () {
    let errors = this.get('fieldErrors');
    return (errors.length > 0);
  }),

  fieldErrors: Ember.computed('errors.@each', 'field', function () {
    let field = this.get('field');
    let error = (this.get('errors.' + field) || []);
    if (Ember.isEmpty(error)) {
      return error;
    }

    if (Ember.isArray(error)) {
      if (error.get('firstObject.message') === undefined) {
        return error.map(e => ({ message: e }));
      }

      return error;
    }

    return [error];
  }),
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>

templates.components.my-component.hbs

{{yield}}

{{#if hasError}}
  <span class="error">
    {{#each fieldErrors as |error| }}
      {{error.messasge}}
    {{/each}}
  </span>
{{/if}}

tests.helpers.resolver.js

import Resolver from '../../resolver';
import config from '../../config/environment';

const resolver = Resolver.create();

resolver.namespace = {
  modulePrefix: config.modulePrefix,
  podModulePrefix: config.podModulePrefix
};

export default resolver;

tests.test-helper.js

import resolver from './helpers/resolver';
import {
  setResolver
} from 'ember-qunit';

setResolver(resolver);

tests.unit.components.my-component-test.js

import { moduleForComponent, test } from 'ember-qunit';
import hbs from 'htmlbars-inline-precompile';

moduleForComponent('my-component', '');

test('it has errors for a field', function() {
  let component = this.subject();

  component.set('field', 'aField');
  component.set('errors', {
    aField: ['an error!']
  });

  let errors = component.get('fieldErrors');
  let result = errors[0].message;
  let expected = 'an error!';
	equal(result, expected);
});

test('it has an error', function() {
  var component = this.subject();

  component.set('field', 'aField');
  component.set('errors', {
    aField: { message: 'an error!' }
  });

  let hasError = component.get('hasError');
  ok(hasError);
});


test('adds the error to the DOM', function() {
  var component = this.subject();

  component.set('field', 'aField');
  component.set('errors', {
    aField: ['an error!']
  });

  this.append();

  equal(this.$().html(), 'an error!');
});

twiddle.json

{
  "version": "0.8.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": true
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.5.1",
    "ember-data": "2.5.2",
    "ember-template-compiler": "2.5.1"
  }
}