Selenium Overview

Introduction

Within the software industry, once a product reaches the stable manual testing phase, every organization usually thinks of automated testing to save on the costs involved in manual testing. Since testing cost is an important factor for any project, organizations have started preferring open source test automation tools (which have reached a stage where they now rival the commercial ones) instead of investing in costly commercial testing tools. With no licensing costs, open source automation testing tools provide competitive features for automating the testing of software applications as well as Web portals.

A variety of open source automation testing tools is available for almost all types of testing such as functional, Web, UAT, regression, performance etc. Because of the extent to which these open source tools have matured, it’s time to think about them and have them in your QA automation kit. There are also various open source tools available to support the different testing types such as White Box Testing (Unit Testing, for e.g., using JUnit) and Black Box Testing (system/regression testing, for e.g., using Selenium, Sahi, Watir, TestMaker, LogiTest, TestGen4J, FitNesse etc).

The scope of this blog is to cover the basic flow for one of these open source Web testing automation tools – Selenium.

Why Selenium?

Selenium is probably the best option for automated testing of Websites today. It is becoming increasingly popular and it is the first choice of automation testers as well as organizations for automating the testing of Web-based applications for both the GUI as well as the functionality. Selenium can also be used as a unit testing tool for JavaScript. We at Xoriant have been working on Selenium for automating the testing of Web sites developed using AJAX for the pharmaceuticals and travel industries. The following graph shows the popularity of Selenium along with other open source automation testing tools.

Selenium Test Package

Selenium is a package of various test components which consists of the following three major tools. Each one has a specific role in aiding the development of test automation for a Web application.

1. Selenium IDE – A Firefox extension to record test cases and suites.
2. Selenium RC – Used to run tests on different browsers and systems.
3. Selenium Grid – Runs multiple instances of Selenium RC at once.
4. Qualitia and Tellurium – A wrapper for the Selenium engine.

Selenium Modes:

Bases on the components Selenium has following three modes for executing the test cases and test suites:

• Record-Playback mode (Selenium IDE)‏:

In this mode only Selenium IDE is used to record the test scenarios in terms of test cases in firefox. This is a great way to get started to writing tests and group them together to form the test suite. The recorded tests can be exported to many programming languages so that we can tweak them and put them in the testing framework. The test cases and test suites can be replayed back to check the verifications and validations or sent to Selenium RC or Grid for further tweaking.

• Selenium Remote Control (RC) Mode

In this mode Selenium starts multiple browsers (one at a time) and then runs the recorded test-cases which are saved in your language of choice. This helps to enhance the test cases with looping and programming techniques to cover all the required test scenarios and checks.

• Test Runner Mode

In this mode the test cases are recorded ad replayed in the form of HTML tables. This is just one more facility to execute the Selenium IDE as well as RC test cases. This helps to check the test results reports in better manner if not formatted already.

Testing AJAX with Selenium

Selenium IDE – Recording and updating a script
Selenium IDE is the FireFox Add-on provided by the Selenium group. This is very simple and easy to use add-on so that non-programmers can record and create the test scripts for automating web components. These automated test scripts are used as Selenium RC test cases by choosing the language code. i.e. Selenium IDE makes easier to create Selenium RC test cases. (Install Selenium IDE and Selenium RC from Selenium download page).
Selenium IDE is used for:

• Recording and updating the test cases or write them manually in table tab.
• Creating Test Suite by grouping the test cases under one group
• Exporting Test Cases/Suites the supported language and save for Selenium RC to enhance them
• Finding reference of every API and Selense commands
• Debugging test cases by toggling breakpoints through the commands

How commands generated in IDE for AJAX pages:

1. Almost all of the web pages are developed with AJAX technology since web2.0 evolution. While recording the page elements, Selenium IDE locates the page elements/objects using XPath/DOM/CSS. XPaths are found automatically, but you may have to update the specific elements in Xpath manually by looking into the source of the page to make them unique. Firebug is the helpful firefox Add-on for this purpose.
2. Every command has maximum two arguments. The first is usually target element pointed by its ID, name, link, DOM, CSS or XPath and the second is the value to that target element if exists. The selenium IDE commands when saved in the programming language of our choice for selenium RC purpose are called as Selenese.
3. The common commands are open, click, type, assert, verify. Commands beginning with ‘assert’ or ‘verify’ are for checks and verifications. If verify command is used and it fails, it fails the test case and continue to run the remaining tests. If assert command is used and it fails, the test case is aborted and stops to run the remaining tests.
4. For synchronizing the flow of test execution Selenium has commands ending with ‘AndWait’, it tells Selenium to wait for the page to load after the action has been done. However, it fails when using AJAX calls. In this case you have to use ‘WaitFor’ commandsmand