```ruby
require 'test_helper'
require 'integration/concerns/authentication'

class AdCreationTest < ActionDispatch::IntegrationTest
  include Authentication

  before { login_as FactoryGirl.create(:user) }

  it 'can have pictures of 5 megabytes or less' do
    with_file_of_size(5.megabytes) do |path|
      fill_ad_form(path)

      page.assert_no_text('Imagen debe estar entre 0 Bytes y 5 MB')
    end
  end

  it 'cannot have pictures bigger than 5 megabytes' do
    with_file_of_size(6.megabytes) do |path|
      fill_ad_form(path)

      page.assert_text('Imagen debe estar entre 0 Bytes y 5 MB')
    end
  end

  private

  def fill_ad_form(file_path)
    visit new_ad_path
    attach_file :image, file_path
    fill_in 'Título de tu anuncio:', with: 'File'
    fill_in 'Cuerpo del anuncio', with: 'My gift is a file full of equis'
    click_button 'Enviar'
  end

  def with_file_of_size(size)
    Tempfile.create('foo') do |f|
      (size / 2**20).times { f.write('x' * 2**20) }
      f.close

      yield(f.path)
    end
  end
end
```

Rename helper method for clarity
user
```ruby
require 'test_helper'
require 'integration/concerns/authentication'

class AdCreationTest < ActionDispatch::IntegrationTest
  include Authentication

  before { login_as FactoryGirl.create(:user) }

  it 'can have pictures of 5 megabytes or less' do
    with_file_of_size(5.megabytes) do |path|
      submit_ad_form(path)

      page.assert_no_text('Imagen debe estar entre 0 Bytes y 5 MB')
    end
  end

  it 'cannot have pictures bigger than 5 megabytes' do
    with_file_of_size(6.megabytes) do |path|
      submit_ad_form(path)

      page.assert_text('Imagen debe estar entre 0 Bytes y 5 MB')
    end
  end

  private

  def submit_ad_form(file_path)
    visit new_ad_path
    attach_file :image, file_path
    fill_in 'Título de tu anuncio:', with: 'File'
    fill_in 'Cuerpo del anuncio', with: 'My gift is a file full of equis'
    click_button 'Enviar'
  end

  def with_file_of_size(size)
    Tempfile.create('foo') do |f|
      (size / 2**20).times { f.write('x' * 2**20) }
      f.close

      yield(f.path)
    end
  end
end
```
assistant