New Twiddle

controllers.application.js

import Ember from 'ember';

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

controllers.some-modal.js

import Ember from 'ember';

export default Ember.Controller.extend({
  
});

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  
  actions: {
    showModal() {
      console.log('showModal');
    this.render('some-modal', {
        into: 'application',
        outlet: 'modal',
        controller: this.controllerFor('some-modal')
      });
    },
    closeModal() {
       console.log('closeModal');
      this.disconnectOutlet({
        outlet: 'modal',
        parentView: 'application'
      });
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<button {{action 'showModal'}}>Show Modal</button>
<br>
<br>

{{outlet 'modal'}}

templates.some-modal.hbs

This is some Modal

<button {{action 'closeModal'}}>Close Modal</button>

tests.helpers.destroy-app.js

import Ember from 'ember';

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

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

setResolver(resolver);

twiddle.json

{
  "version": "0.11.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.10.2",
    "ember-data": "2.11.0",
    "ember-template-compiler": "2.10.2",
    "ember-testing": "2.10.2"
  },
  "addons": {}
}