Native find helper

Adds find helper, which uses setting for rootElement, default is #ember-testing. Returns either HTMLElement or a NodeList.

To use a different value from your config/environment module, add to tests/test-helper.js …

import settings from 'ember-native-dom-helpers/test-support/settings';
import config from '../config/environment';
const { APP: { rootElement } } = config;

settings.rootElement = rootElement || settings.rootElement;