Basics of Continuous Integration (CI)

Almost every methodological approach in software development aims to reduce development time and produce more qualified products. Continuous Integration (CI) also aims to reduce development time. Basically, CI is software development practice that developers need to check-out their codes in their local development environment and than integrate them to shared repository. According to Martin Fowler who known by his studies about CI, there should be at least one integration to shared repository done everyday, but the frequency of integration is expected to be more than one integration. By this way, test activities are performed during every integration and problems caused by the integration can be minimized. As it is emphasized in this blog, CI says us as "pay me now, or pay me more later". If we look at the history of CI, it goes back to extreme programming (XP) which advocates that there should be frequently code merged to master to cover unstable requirements of customers. CI was applied as a part of XP by merging local codes to shared code and than test it and than develop for next integration and this cycle should be performed everyday. Therefore CI is very effective practice for iterative software development.

Application of Continuous Integration

As I tried to explain to apply the CI practices developers get the latest code base from shared repository than add their new codes and than merged them to the shared repository again. This process should be performed several time in a day. In this procedure, testing should be automated and manual testing can be also performed after new codes release to source code. If any failure is detected by integration server or test environment, it should be reported to related people and they fixed it and merged to new code into the CI again. As we know that the latest code causes this bug and after the "good code" works well. Therefore, efficiency of CI can be seen by this way as it is said to be "fix your bug early and often". The below picture show the philosophy of CI in basic for general software development methodology.

Application of Continuous Integration

As in the picture, in middle of the process there is a source code control system which controls the code when the developers push their code into source code. Than continuous integration checks the system if there is anything wrong with that is not in "good code". If any any bug find in the source code it send failure notification to developers (actually if error occur, everyone should know it). If the CI doesn't report error about integration, the new "good code" is taken into source code test environment for regression and advance testing. However this explanation doesn't reflect everything for agile which is very popular software development methodology. Let's look at the process which is drawn by Rational for agile and test driven development.

CI for Agile and Test Driven Development

For agile development, there are product backlog and sprint to develop the product step by step belonging to the iterative approach. As seen for TDD, unit tests are written first than product code should be written until all the test are passed. Steps like this:

For the sprint, take the requirements
Write unit tests
Develop product code until every test case are passed
Run unit tests
Merge new code into shared repository
CI, integration test and regression testing
If any error, report it quickly; If no error, merge new code to product
Next sprint starts

Advantages of Continuous Integration

Risk are reduced
Bug can be found and reported quickly
Project visibility is increase
Keeping development branch updated is easier
Reduce number of regression test
Product for test is ready every time
Enforce you to have better development process

Disadvantages of Continuous Integration

There should be additional tools such CI, Test. List of tools click here
There should change in development mindset
Required more discipline
Refactoring may be difficult because of unstable code base

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\seleni...

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 al...

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...

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 s...

TEST THE RISK!

Search This Blog