old_contents: import Ember from 'ember'
  const {merge, run} = Ember
  import Application from '../../app'
  import config from '../../config/environment'
  
  export default function startApp (attrs) {
    let application
  
    let attributes = merge({}, config.APP)
    attributes = merge(attributes, attrs) // use defaults, but you can override;
  
    run(() => {
      application = Application.create(attributes)
      application.setupForTesting()
      application.injectTestHelpers()
    })
  
    return application
  }
  
new_contents: /* eslint-disable ember-standard/destructure */
  import Ember from 'ember'
  const {run} = Ember
  import Application from '../../app'
  import config from '../../config/environment'
  
  const assign = Object.assign || Ember.assign || Ember.merge
  
  export default function startApp (attrs) {
    let application
  
    let attributes = assign({}, config.APP)
    attributes = assign(attributes, attrs) // use defaults, but you can override;
  
    run(() => {
      application = Application.create(attributes)
      application.setupForTesting()
      application.injectTestHelpers()
    })
  
    return application
  }
  
subject: put back the assign stuff