How can I run Selenium (used through Capybara) at a lower speed? - ruby

Question

By default Selenium runs as fast as possible through the scenarios I defined using Cucumber.
I would like to set it to run at a lower speed, so I am able to capture a video of the process.
I figured out that an instance of Selenium::Client::Driver has a set_speed method. Which corresponds with the Java API.
How can I obtain an instance of the Selenium::Client::Driver class? I can get as far as page.driver, but that returns an instance of Capybara::Driver::Selenium.

Answer 1

Thanks to http://groups.google.com/group/ruby-capybara/msg/6079b122979ffad2 for a hint.
Just a note that this uses Ruby's sleep, so it's somewhat imprecise - but should do the job for you. Also, execute is called for everything so that's why it's sub-second waiting. The intermediate steps - wait until ready, check field, focus, enter text - each pause.
Create a "throttle.rb" in your features/support directory (if using Cucumber) and fill it with:
require 'selenium-webdriver'
module ::Selenium::WebDriver::Firefox
class Bridge
attr_accessor :speed
def execute(*args)
result = raw_execute(*args)['value']
case speed
when :slow
sleep 0.3
when :medium
sleep 0.1
end
result
end
end
end
def set_speed(speed)
begin
page.driver.browser.send(:bridge).speed=speed
rescue
end
end
Then, in a step definition, call:
set_speed(:slow)
or:
set_speed(:medium)
To reset, call:
set_speed(:fast)

Answer 2

This will work, and is less brittle (for some small value of "less")
require 'selenium-webdriver'
module ::Selenium::WebDriver::Remote
class Bridge
alias_method :old_execute, :execute
def execute(*args)
sleep(0.1)
old_execute(*args)
end
end
end

Answer 3

As an update, the execute method in that class is no longer available. It is now here only:
module ::Selenium::WebDriver::Remote
I needed to throttle some tests in IE and this worked.

Answer 4

The methods mentioned in this thread no longer work with Selenium Webdriver v3.
You'll instead need to add a sleep to the execution command.
module Selenium::WebDriver::Remote
class Bridge
def execute(command, opts = {}, command_hash = nil)
verb, path = commands(command) || raise(ArgumentError, "unknown command: #{command.inspect}")
path = path.dup
path[':session_id'] = session_id if path.include?(':session_id')
begin
opts.each { |key, value| path[key.inspect] = escaper.escape(value.to_s) }
rescue IndexError
raise ArgumentError, "#{opts.inspect} invalid for #{command.inspect}"
end
Selenium::WebDriver.logger.info("-> #{verb.to_s.upcase} #{path}")
res = http.call(verb, path, command_hash)
sleep(0.1) # <--- Add your sleep here.
res
end
end
end
Note this is a very brittle way to slow down the tests since you're monkey patching a private API.

Answer 5

I wanted to slow down the page load speeds in my Capybara test suite to see if I could trigger some intermittently failing tests. I achieved this by creating an nginx reverse proxy container and sitting it between my test container and the phantomjs container I was using as a headless browser. The speed was limited by using the limit_rate directive. It didn't help me to achieve my goal in the end, but it did work and it may be a useful strategy for others to use!