Double click doesn't actually double click

[lfdebrux]

Describe the bug

I'm using Ferrum via Cuprite and Capybara to test what happens when a HTML form submit button is double clicked on.

However, the behaviour that Ferrum does for Node#click(mode: double) doesn't seem to be treated by the submit button in the same way a human double clicking would, instead it is seen as a single click.

To Reproduce

The following simple web app and browser automation script demonstrate the problem:

# click_count_server.rb

require 'sinatra'

globals = { click_count: 0 }

get '/' do
  globals[:click_count] = 0
  <<~HTML
  <form method="post">
   <button id="clickCount">Click</button>
  </form>
  HTML
end

post '/' do
  globals[:click_count] += 1
  sleep 0.1
  <<~HTML
  <form method="post">
   <button id="clickCount">Click count: #{globals[:click_count]}</button>
  </form>
  HTML
end

require 'ferrum'

browser = Ferrum::Browser.new
browser.go_to('http://localhost:4567')
browser.at_css('button#clickCount').click(mode: double)

Node#click(mode: double) on a submit button results in the button being clicked once when double click with a mouse by a human would result in the button being clicked twice.

Expected behavior

I would expect Node#click(mode: double) to result in two clicks being registered by the submit button.

Screenshots

Kapture.2025-03-28.at.14.41.19.mp4

Desktop (please complete the following information):

• OS: macOS
• Browser [Chrome Version 134.0.6998.166 (Official Build) (arm64)]
• Version [v 0.15]

Additional context

I think the problem may be in

ferrum/lib/ferrum/node.rb

Lines 76 to 79 in b727708

	when :double
	page.mouse.move(x: x, y: y)
	page.mouse.down(modifiers: modifiers, count: 2)
	page.mouse.up(modifiers: modifiers, count: 2)

I would expect each mouse.down to be followed by a mouse.up before the next mouse.down, but it looks like instead what happens is two mouse.down events followed by two mouse.up events.

[lfdebrux]

After a little experimenting, I found I could get the behaviour I expected with

def double_click(node)
  x, y = node.find_position
  mouse = node.page.mouse
  mouse.move(x:, y:)
  mouse.down
  mouse.up
  sleep(0.05)
  mouse.down
  mouse.up
end

[route]

This is incorrect example, it's 2 single clicks with sleep between them rather than double click.
There's a test for double click #533
There's no mistake here in count: 2 this is how double click is sent using CDP