thing_feature_spec.rb

feature 'Thing' do
  scenario 'Creating a thing' do
    when_creating_thing
    then_should_see_thing_created
  end

  scenario 'Updating a thing' do
    when_updating_thing
    then_should_see_thing_updated
  end

  scenario 'Updating a thing with already taken name' do
    when_updating_thing_with_already_taken_name
    then_should_see_already_taken_name_error
  end

  def when_creating_thing
    visit new_thing_path
    fill_in :name, with: thing_name
    click_button 'create thing'
  end
  
  def then_should_see_thing_created
    assert_thing_in_response
  end

  def when_updating_thing
    update_things_name
  end
  
  def then_should_see_thing_updated
    assert_thing_in_response
  end

  def when_updating_thing_with_already_taken_name
    create(:thing, name: thing_name)
    update_things_name
  end
  
  def then_should_see_already_taken_name_error
    expect(page).to have_content('already taken')
  end

  private 

  let(:thing_name) { 'Thingy' }

  def update_things_name
    visit edit_thing_path(create(:thing))
    fill_in :name, with: thing_name
    click_button 'update thing'
  end

  def assert_thing_in_response
    expect(page).to have_content(thing_name)
  end
end