Improved handling of TinyMCE with error logging and guard checks

tinymce_spec_helper.rb

module TinyMCESpecHelper
  # Fill in a TinyMCE editor with the specified value.
  # Pass in the same id you give to TinyMCE, (such as "editorContent")
  # *not* TinyMCE's generated one.
  # 
  # NOTE: The first argument is not a css selector, just an element id.
  #
  # May require selenium chromedriver!
  # Adapted from https://gist.github.com/eoinkelly/69be6c27beb0106aa555
  #
  def fill_in_tinymce(editor_id, value)
    expect(page).to have_selector("##{editor_id}", visible: false)

    # wait until the TinyMCE editor instance is ready. This is required for cases
    # where the editor is loaded via XHR.
    count = 0
    until page.evaluate_script("tinyMCE.get('#{editor_id}') !== null")
      sleep 0.5
      if (count += 1) > 10 # rubocop:disable Style/Next
        log = page.driver.browser.manage.logs.get('browser')
        errors = log.map.with_index { |e, i| "#{i + 1}: #{e}" }.join("\n")
        raise "cannot find TinyMCE editor:\n#{errors}"
      end
    end

    js = "tinyMCE.get('#{editor_id}').setContent('#{value}')"
    page.execute_script(js)
  end
end