Class: Watir::Element

Inherits:
Object show all
Defined in:
lib/testable/extensions/dom_observer.rb

Constant Summary collapse

OBSERVER_FILE = 
"/dom_observer.js".freeze
DOM_OBSERVER = 
File.read("#{File.dirname(__FILE__)}#{OBSERVER_FILE}").freeze

Instance Method Summary collapse

Instance Method Details

#dom_updated?(delay: 1.1) ⇒ Boolean Also known as: dom_has_updated?, dom_has_changed?, when_dom_updated, when_dom_changed

This method makes a call to ‘execute_async_script` which means that the DOM observer script must explicitly signal that it is finished by invoking a callback. In this case, the callback is nothing more than a delay. The delay is being used to allow the DOM to be updated before script actions continue.

The method returns true if the DOM has been changed within the element context, while false means that the DOM has not yet finished changing. Note the wording: “has not finished changing.” It’s known that the DOM is changing because the observer has recognized that. So the question this method is helping to answer is “has it finished?”

Consider the following element definition:

p :page_list, id: 'navlist'

You could then do this:

page_list.dom_updated?

That would return true if the DOM content for page_list has finished updating. If the DOM was in the process of being updated, this would return false. You could also do this:

page_list.wait_until(&:dom_updated?).click

This will use Watir’s wait until functionality to wait for the DOM to be updated within the context of the element. Note that the “&:” is that the object that ‘dom_updated?` is being called on (in this case `page_list`) substitutes the ampersand. You can also structure it like this:

page_list.wait_until do |element|
    element.dom_updated?
end

The default delay of waiting for the DOM to start updating is 1.1 second. However, you can pass a delay value when you call the method to set your own value, which can be useful for particular sensitivities in the application you are testing.

Returns:

  • (Boolean) 


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# File 'lib/testable/extensions/dom_observer.rb', line 46

def dom_updated?(delay: 1.1)
  element_call do
    begin
      driver.manage.timeouts.script_timeout = delay + 1
      driver.execute_async_script(DOM_OBSERVER, wd, delay)
    rescue Selenium::WebDriver::Error::JavascriptError => e
      # This situation can occur if the script execution has started before
      # a new page is fully loaded. The specific error being checked for
      # here is one that occurs when a new page is loaded as that page is
      # trying to execute a JavaScript function.
      retry if e.message.include?(
        'document unloaded while waiting for result'
      )
      raise
    ensure
      # Note that this setting here means any user-defined timeout would
      # effectively be overwritten.
      driver.manage.timeouts.script_timeout = 1
    end
  end
end