Untitled

expected: "User-agent: *nDisallow:nnSitemap: https://prj.org/sitemap.xmln"
        got: "<html><head><link rel="alternate stylesheet" type="text/css" href="resource://content-accessible/plaintext.css" title="Wrap Long Lines"></head><body><pre>User-agent: *nDisallow:nnSitemap: https://prj.org/sitemap.xmln</pre></body></html>"

Capybara.register_driver :firefox_headless do |app|
  options = ::Selenium::WebDriver::Firefox::Options.new
  options.headless!
  options.add_preference 'plain_text.wrap_long_lines', false

  Capybara::Selenium::Driver.new app, browser: :firefox, options: options
end

Capybara.register_driver :firefox_headless do |app|
  options = ::Selenium::WebDriver::Firefox::Options.new
  options.headless!

  profile = Selenium::WebDriver::Firefox::Profile.new
  profile['plain_text.wrap_long_lines'] = false

  Capybara::Selenium::Driver.new app, browser: :firefox, options: options, profile: profile
end