Selenium is a high quality open source test automation tool for web application testing. Selenium runs in Internet Explorer, Mozilla and Firefox on Windows, Linux, and Macintosh, Safari on the Mac, with plans to support Safari on iPhone soon. Selenium provides a rich set of testing functions specifically geared to the needs of testing of a web application. These operations are highly flexible, allowing many options for locating UI elements and comparing expected test results against actual application behavior. Selenium provides a test domain specific language (DSL) to write tests in a number of popular programming languages, including Java, Ruby, Groovy, Python, PHP, and Perl.
There are three variants of Selenium testing, which can be used in isolation or in combination to create complete automation suite for your web applications.
- Selenium IDE
- Selenium Core
- Selenium Remote Control
In Selenium Core the tests scripts (written in HTML) and the Selenium Test Runner (written in Javascript) are uploaded to the same web server that hosts the application you are trying to test. It is a simpler form of Selenium, and suitable for non-developers, but it has some inherent limitations.
1. Selenium IDE is the easiest way to use Selenium and most of the time it also serves as a starting point for your automation. Selenium IDE comes as an extension to the Firefox web browser. This can be installed from either openqa or mozilla distribution site.
2. Selenium-RC allows the test automation developer to use a programming language for maximum flexibility and extensibility in developing test logic. It allows to develop test cases and test suites in Java (supports JUnit & NGUnit), PHP, Ruby, Python, Perl and even .NET. It is the most flexible setup but requires some development knowledge to set up and use.
3. Selenium Grid allows several Selenium Remote Control servers to be accessed in parallel by Selenium Grid server. This is extremely useful for automated load and stress testing of web applications.
