Capybara & RSPEC: ActionController::UnknownFormat: Error. How do i fix this error?

Question

This is the error when i run the capybara test:

 Failure/Error:
       respond_to do |format|
         #format.html
         format.js
       end

     ActionController::UnknownFormat:
       ActionController::UnknownFormat

This is from the controller file: (uncommenting format.html didn't work)

  def new
    @location = @provider.locations.new
    @address = @location.build_address
    @addresses = []
    respond_to do |format|
      #format.html
      format.js
    end

This is the capybara code

describe "this tab" do
    it "shows data" do 
      visit locations_profile_path(@provider)
      expect(current_path).to eq("/profile/#{@provider.id}/locations")
      expect(page).to have_content("All Practice Locations")
      expect(page).to have_content('Add New Location')
      Capybara.default_max_wait_time = 20
      click_on 'Add New Location'
end
end

score 1 · Answer 1 · answered Oct 05 '21 at 01:25

You state that uncommenting format.html didn't work, but I'm betting it failed with a different error message, because you don't have an html view. I'm also assuming that the error message you're seeing is coming from the click_on 'Add New Location' line which appears to the only part of your test that would call a new action. Without seeing the code in your page triggered by clicking on 'Add New Location' I can't be 100% sure what the issue is, but based on the error I'm guessing that you're not actually using the capybara-webkit driver (even though the question is tagged with that). Really you shouldn't be using the capybara-webkit driver nowadays anyway since it was obsolete years ago. Rather you should be looking at one of the up-to-date maintained drivers like Selenium, etc. Depending on which version of Rails you're using and what type of tests you're writing you'll want to either look at Rails/RSpecs driven_by (for Rails 6+ and system specs) or Capybaras default_driver and javascript_driver settings if writing feature specs - click_on 'Add New Location'. If you're not correctly selecting the driver to be used then it would default to the rack-test driver which doesn't support JS and therefore would never make a request for a JS format response.

Other comments on your test

You should never be using RSpecs general matchers (eq, etc) with Capybara related info
You should not be setting Capybara global settings (default_max_wait_time) inside your test. Instead set the per command options for max wait time, or use using_wait_time if needed for multiple commands.
There's no point checking for content that you then attempt to click, since the click_on is also checking for its existence

taking those into account your test should be written more like

visit locations_profile_path(@provider)
expect(page).to have_current_path("/profile/#{@provider.id}/locations")
expect(page).to have_content("All Practice Locations")
click_on 'Add New Location', wait: 20

Capybara & RSPEC: ActionController::UnknownFormat: Error. How do i fix this error?

1 Answers1