message: improve loading indicator test
diff: import { module, test } from 'qunit';
  import { setupRenderingTest } from 'ember-qunit';
  import { render } from '@ember/test-helpers';
  +import injectCustomAssertions from 'ember-osf-web/tests/helpers/inject-custom-assertions';
  import hbs from 'htmlbars-inline-precompile';
  module('Integration | Component | loading indicator', function(hooks) {
  setupRenderingTest(hooks);
  + injectCustomAssertions(hooks);
  - test('it renders', async function(assert) {
  + test('light', async function(assert) {
  await render(hbs`{{loading-indicator}}`);
  - assert.equal(this.$().text().trim(), '');
  + assert.hasText(this.element, '', 'is empty element');
  + assert.hasClass(this.element.querySelector('div.ball-scale'), 'ball-light');
  + });
  +
  + test('dark', async function(assert) {
  + await render(hbs`{{loading-indicator dark=true}}`);
  + assert.hasText(this.element, '', 'is empty element');
  + assert.hasClass(this.element.querySelector('div.ball-scale'), 'ball-dark');
  });
  });
  