Confusion of Using Selenium for Performance Testing

Time to time, I see some questions about integration test automation script to performance testing tool on Stackoverflow. There is a confusion about performance testing and test automation for whom newly started performance testing after doing some test automation. It is demanded that they have some automation code and want to use these scripts for performance testing to simulate user behaviour. Theoretically it seems a very good idea that tons of users are performing some cases and you are capturing the response time and finding bottle neck in terms of client side. However this is not applicable in practice because there are lots of obstacle to handle. The followings outline the obstacles and misunderstandings you will face, for the idea.

I can open some browsers and simulate real user behaviour

Automation scripts run over a browser, for web project. Most of the application are becoming as web app. For GUI based application what the hack test automation will have a role on performance testing. Crazy thing I have ever heard. If you want to test the client side performance problem, it is another case. For web application you need to test the services first, and if every thing is performing well enough then you can check the GUI related problems as in testing the mobile application too. Therefore you have to create an instance of browser for each users so you have a limit for number of browsers, let's say it is no more than a 2K. See that each Chromedriver consumes %0,2 memory of total physical RAM on idle, which means I can open, but not to send some commands, only 500 Chromedrivers.

No Need Browsers for Headless Testing

Headless testing doesn't open a browser so it is cheap for testing. Idea behind the headless browser is reducing the time for loading of user interface related things like photos, tables, JavaScript etc. and making light weighted version of a browser. With this way you can make your automation test faster but you have stick what it requires. Even it is somehow faster than a real browser, and it also cheaper in terms of consuming ram and processor, there is a limit for the number of headless browsers.

Problem of Handling Browsers

Every browser needs to have a valid driver to drive the automation code throughout the connection protocol. This is needed to send commands to browser to interact with the web objects. To run many cases parallel, you need to have a configuration for

Dom should be ready to be able to handle the commands
Handling waiting time is another problem since the time is the major concern for performance testing
Physical needs for sending, rendering and handling commands
The performance indicators, how to see that problematic parts of the test
Managing test environments

Why This is Becoming a Request

The idea Selenium can be used for performance testing is inspired by a feature that Jmeter has a Webdriver plug-in to run Selenium script in terms of testing client side performance. With this plug-in, you run some Selenium scripts to get time consuming for completing the Selenium script. Another meaning of this, it calculates the overall time that a client most probably face for the case under predefined amount of loads. This does not mean that you are running the Selenium to create loads. As the following is a part of the guideline of the plug-in:

for the Web Driver use case, the reader should be prudent in the number of threadsthey will create as each thread will have a single browser instance associated with it. Each browser consumes a significant amount of resources, and a limit should be placed on how many browsers the reader should create.

What is more Practical for The Client Side Performance Testing

When you have a ready performance testing script and have some scripts for automated test cases then you are good to test the client side performance. Instead of injecting Selenium script to your performance testing tools you can run the performance scripts to load the server as demanded load then run the automation script and calculate the time taken for completion of test cases.

Selenium Error "Element is not currently interactable and may not be manipulated"

Selenium webdriver can drive different browsers like as Firefox, Chrome or Internet Explorer. These browsers actually cover the majority of internet users, so testing these browsers possibly covers the 90% of the internet users. However, there is no guaranty that the same automation scripts can work without a failure on these three browsers. For this reason, automation code should be error-prone for the browsers you want to cover. The following error is caught when the test script run for Chrome and Internet Explorer, but surprisingly there is no error for the Firefox. Selenium gives an error like below: Traceback (most recent call last): File "D:\workspace\sample_project\sample_run.py", line 10, in <module> m.login() File "D:\workspace\ sample_project \test_case_imps.py", line 335, in login driver.find_element_by_id("id_username").clear() File "C:\Python27\lib\site-packages\selenium-2.35.0-py2.7.egg\selenium\webdriver\r

Change Default Timeout and Wait Time of Capybara

One of the biggest challenge for automation is handling timeout problem. Most of the time, timeout is 60 seconds but it may sometimes not enough if you have badly designed asynchronous calls or the third party ajax calls. This makes handling timeout more complex. set large enough to tolerate network related problems. For Selenium based automation frameworks, like Capybara, default Webdriver timeout is set to Net::ReadTimeout (Net::ReadTimeout) Changing ReadTimeout If you have timeout problem for Capybara, it gives an error like above. This means that the page is not fully loaded in given timeout period. Even you can see that page is loaded correctly but webdriver wait until the Ajax calls finish. class BufferedIO #:nodoc: internal use only def initialize (io) @io = io @read_timeout = 60 @continue_timeout = nil @debug_output = nil @rbuf = '' end . . . . . def rbuf_fill beg

Create an Alias for Interactive Console Work: Selenium and Capybara

If you are working on shell most of the time Aliases are very helpfull and time saving. For testing purposes you can use Alias for getting ready your test suites. In this post, I want to explain both running Selenium and Capybara on console and creating aliases for each. This post is for Windows machines, if you are using Unix-like see this post . Creating Scripts for Selenium and Capybara First of all, it is assumed that you have installed Selenium and Capybara correctly and they work on your machines. If you haven't installed, you can see my previous posts. I am using the Selenium with Python and the Capybara with Ruby. You can use several different language for Selenium but Capybara works only with Ruby. Create scripts in a directory called scripts (in your home folder, like as ~/scripts ) for your automation tool as following, save them as capybara.rb, sel.py : Creating Aliases Depends on your favourite shell, you need to add the alias to .bashrc bash

Page-Object Pattern for Selenium Test Automation with Python

Page-object model is a pattern that you can apply it to develop efficient automation framework. With the page-model, it is possible to minimize maintenance cost. Basically page-object means that your every page is inherited from a base class which includes basic functionalities for every page. If you have some new functionalities that every page should have, you can simple add it to the base class. Base class is like the following: In this part we are creating pages which are inherited from base page. Every page has its own functionalities written as python functions. Some functions return to a new page, it means that these functions leave the current page and produce a new page. You should write as much as functions you need in the assertion part because this is the only part you can use the webdriver functions to interact with web pages . This part can be evaluate as providing data to assertion part. The last part is related to asserting your test cases against to the

Performance Testing on CI: Locust is running on Jenkins

For a successful Continuous Integration pipeline, there should be jobs for testing the performance of the application. It is necessary if the application is still performing well. Generally performance testing is thought as kinds of activities performed one step before going to live. In general approach it is true but don't forget to test your application's performance as soon as there is an testable software, such as an api end point, functions, and etc. For CI it is a good approach to testing performance after functional testing and just before the deployment of next stage. In this post, I want to share some info about Jenkins and Locust. In my previous post you can find some information about Locust and Jenkins. Jenkins operates the CI environment and Locust is a tool for performance testing. To run the Locust on Jenkins you need command line arguments which control the number of clients , hatch rate, running locust without web interface and there should be so

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