component test

components.blog-post.js

import Component from '@glimmer/component';

export default class BlogPost extends Component {
}

router.js

import EmberRouter from '@ember/routing/router';
import config from './config/environment';

const Router = EmberRouter.extend({
  location: 'none',
  rootURL: config.rootURL
});

Router.map(function() {
});

export default Router;

routes.index.js

import Route from '@ember/routing/route';
import {debug} from '@ember/debug'

//export default class index extends Route {
export default Ember.Route.extend({
  model() {
    //alert();
    return [{
    	id: 0,
      title: 'book a',
    	body: 'test a'
    },
    {
      id: 1,
    	title: 'book b',
    	body: 'test b'
    },{
      id: 2,
    	title: 'book c',
    	body: 'test c'
    }]
  }
});

templates.application.hbs

application.hbs

{{outlet}}

templates.components.blog-post.hbs

<article>
  <h1>{{this.title}}</h1>
  <p>{{yield}}</p>
</article>

templates.index.hbs

index.hbs

{{#each this.model as |post|}}
  <blog-post title={{post.title}}>
    {{post.body}}
  </blog-post>
{{/each}}

{{outlet}}

tests.helpers.destroy-app.js

import { run } from '@ember/runloop';

export default function destroyApp(application) {
  run(application, 'destroy');
}

tests.helpers.start-app.js

import Ember from 'ember';
import Application from '../../app';
import config from '../../config/environment';

const { run } = Ember;
const assign = Ember.assign || Ember.merge;

export default function startApp(attrs) {
  let application;

  let attributes = assign({rootElement: "#test-root"}, config.APP);
  attributes.autoboot = true;
  attributes = assign(attributes, attrs); // use defaults, but you can override;

  run(() => {
    application = Application.create(attributes);
    application.setupForTesting();
    application.injectTestHelpers();
  });

  return application;
}

tests.test-helper.js

import Application from '../app';
import config from '../config/environment';
import { setApplication } from '@ember/test-helpers';
import { start } from 'ember-qunit';
import { assign } from '@ember/polyfills';

let attributes = assign({ rootElement: '#main' }, config.APP);
setApplication(Application.create(attributes));

start();

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.1.4",
    "ember-template-compiler": "3.1.4",
    "ember-testing": "3.1.4"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}