Testing an attachment CSV with RSpec and controllers.

Ever send down a CSV from a controller like this:

  def index
    @users = User.all

    respond_to do |format|
      format.csv { send_data @users.to_csv, filename: "users-#{Date.today}.csv" }
    end
  end

And then wonder how you can test the contents as well as the filename, and the fact that it's supposed to be a download?

To check the filename, look at response.headers['Content-Disposition'].

expect(response.headers['Content-Disposition'])
  .to eq 'attachment; filename=users-2020-10-23.csv'

To check the contents, look at response.body:

expect(response.body).to eq <<~CSV
  First Name,Last Name
  Andrew,Smith
CSV