RSpec.describe InterestsController, type: :controller do

  describe 'POST #create' do

    context 'with valid attributes' do

      it 'redirects to referer' do

        from about_path

        post :create, params: { interest: attributes_for(:interest) }

        expect(response).to redirect_to about_url

      end

    end

  end

end

module RedirectBack

  def from(url)

    request.env['HTTP_REFERER'] = url

  end

end

RSpec.configure do |config|

  config.include RedirectBack

end