NoMethodError: undefined method `strings' for Puma::Events:Class

Question

I'm running a pretty simple test, which requires javascript, just to check the index loads and an element is there, something like:

class ProfitsTest < ApplicationSystemTestCase
  setup do
    @admin = users(:admin)
    @admin.confirm
    sign_in @admin
  end

  test 'visiting the index' do
    # Index only test
    visit profits_url
    assert_selector 'h1', text: '計算表'
  end
end

My config for capybara looks like this (just getting rid of Puma boot logs):

require 'test_helper'

class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
  driven_by :selenium, using: :headless_chrome # :chrome
  Capybara.server = :puma, { Silent: true }
  Selenium::WebDriver.logger.ignore(:browser_options)
end

And here's the error I'm getting:

#<Thread:0x000000010f82b2d8 /Users/cody/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/capybara-3.37.1/lib/capybara/server.rb:76 run> terminated with exception (report_on_exception is true):
/Users/cody/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/capybara-3.37.1/lib/capybara/registrations/servers.rb:32:in `block in <main>': undefined method `strings' for Puma::Events:Class (NoMethodError)

  events = conf.options[:Silent] ? ::Puma::Events.strings : ::Puma::Events.stdio
                                                 ^^^^^^^^
    from /Users/cody/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/capybara-3.37.1/lib/capybara/config.rb:64:in `block in server='
    from /Users/cody/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/capybara-3.37.1/lib/capybara/server.rb:77:in `block in boot'
E

Error:
ProfitsTest#test_visiting_the_index:
NoMethodError: undefined method `strings' for Puma::Events:Class
    /Users/cody/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/capybara-3.37.1/lib/capybara/registrations/servers.rb:32:in `block in <main>'
    /Users/cody/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/capybara-3.37.1/lib/capybara/config.rb:64:in `block in server='
    /Users/cody/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/capybara-3.37.1/lib/capybara/server.rb:77:in `block in boot'

Error:
ProfitsTest#test_visiting_the_index:
NoMethodError: undefined method `strings' for Puma::Events:Class
    /Users/cody/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/capybara-3.37.1/lib/capybara/registrations/servers.rb:32:in `block in <main>'
    /Users/cody/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/capybara-3.37.1/lib/capybara/config.rb:64:in `block in server='
    /Users/cody/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/capybara-3.37.1/lib/capybara/server.rb:77:in `block in boot'


rails test test/system/profits_test.rb:20

I guess I've got an error to debug but the logger isn't working? If I change Silent: true to Silent: False, it gives me the same No Method Error for stdio. So something must be wrong with Puma? I'm using rails (6.1.7), puma (6.0.0) and capybara (3.37.1).

I'm stumped.

Answer 1

The released version of Capybara doesn’t support Puma 6. You can use the master branch of Capybara, use Puma 5.x, or write your own server registration config.