Introducing Selenium??
To Automate or Not to Automate? That is the Question!??
Is automation always advantageous? When should one decide to automate test cases?
It is not always advantageous to automate test cases. There are times when manual testing may be more appropriate. For instance, if the application’s user interface will change considerably in the near future, then any automation would need to be rewritten. Also, sometimes there simply is not enough time to build test automation. For the short term, manual testing may be more effective. If an application has a very tight deadline, there is currently no test automation available, and it’s imperative that the testing get done within that time frame, then manual testing is the best solution.
However, automation has specific advantages for improving the long-term efficiency of a software team’s testing processes. Test automation supports:
- Frequent regression testing
- Rapid feedback to developers during the development process
- Virtually unlimited iterations of test case execution
- Customized reporting of application defects
- Support for Agile and eXtreme development methodologies
- Disciplined documentation of test cases
- Finding defects missed by manual testing
Test Automation for Web Applications??
Many, perhaps most, software applications today are written as web-based applications to be run in an Internet browser. The effectiveness of testing these applications varies widely among companies and organizations. In an era of continuously improving software processes, such as eXtreme programming (XP) and Agile, it can be argued that disciplined testing and quality assurance practices are still underdeveloped in many organizations. Software testing is often conducted manually. At times, this is effective; however there are alternatives to manual testing that many organizations are unaware of, or lack the skills to perform. Utilizing these alternatives would in most cases greatly improve the efficiency of their software development by adding efficiencies to their testing.
Test automation is often the answer. Test automation means using a tool to run repeatable tests against the target application whenever necessary.
There are many advantages to test automation. Most are related to the repeatability of the tests and the speed at which the tests can be executed. There are a number of commercial and open source tools available for assisting with the development of test automation. Selenium is possibly the most widely-used open source solution. This user’s guide will assist both new and experienced Selenium users in learning effective techniques in building test automation for web applications.
This guide introduces Selenium, teaches its most widely used features, and provides useful advice in best practices accumulated from the Selenium community. Many examples are provided. Also, technical information on the internal structure of Selenium and recommended uses of Selenium are provided as contributed by a consortium of experienced Selenium users. It is our hope that this guide will get additional new users excited about using Selenium for test automation. We hope this guide will assist in “getting the word out” that quality assurance and software testing have many options beyond what is currently practiced. We hope this user’s guide and Selenium itself provide a valuable aid to boosting the reader’s efficiency in his or her software testing processes.
Introducing Selenium??
Selenium is a robust set of tools that supports rapid development of test automation for web-based applications. 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.
One of Selenium’s key features is the support for executing one’s tests on multiple browser platforms.
Selenium Components??
Selenium is composed of three major tools. Each one has a specific role in aiding the development of web application test automation.
Selenium-IDE??
Selenium-IDE is the Integrated Development Environment for building Selenium test cases. It operates as a Firefox add-on and provides an easy-to-use interface for developing and running individual test cases or entire test suites. Selenium-IDE has a recording feature, which will keep account of user actions as they are performed and store them as a reusable script to play back. It also has a context menu (right-click) integrated with the Firefox browser, which allows the user to pick from a list of assertions and verifications for the selected location. Selenium-IDE also offers full editing of test cases for more precision and control.
Although Selenium-IDE is a Firefox only add-on, tests created in it can also be run against other browsers by using Selenium-RC and specifying the name of the test suite on the command line.
Selenium-RC (Remote Control)??
Selenium-RC allows the test automation developer to use a programming language for maximum flexibility and extensibility in developing test logic. For instance, if the application under test returns a result set, and if the automated test program needs to run tests on each element in the result set, the programming language’s iteration support can be used to iterate through the result set, calling Selenium commands to run tests on each item.
Selenium-RC provides an API (Application Programming Interface) and library for each of its supported languages: HTML, Java, C#, Perl, PHP, Python, and Ruby. This ability to use Selenium-RC with a high-level programming language to develop test cases also allows the automated testing to be integrated with a project’s automated build environment.
Selenium-Grid??
Selenium-Grid allows the Selenium-RC solution to scale for large test suites or test suites that must be run in multiple environments. With Selenium-Grid, multiple instances of Selenium-RC are running on various operating system and browser configurations. Each of these when launching register with a hub. When tests are sent to the hub they are then redirected to an available Selenium-RC, which will launch the browser and run the test. This allows for running tests in parallel, with the entire test suite theoretically taking only as long to run as the longest individual test.
Supported Browsers??
| Browser | Selenium-IDE | Selenium-RC | Operating Systems |
| Firefox 3 | 1.0 Beta-1 & 1.0 Beta-2: Record and playback tests | Start browser, run tests | Windows, Linux, Mac |
| Firefox 2 | 1.0 Beta-1: Record and playback tests | Start browser, run tests | Windows, Linux, Mac |
| IE 8 | Under development | Windows | |
| IE 7 | Test execution only via Selenium-RC* | Start browser, run tests | Windows |
| Safari 3 | Test execution only via Selenium-RC | Start browser, run tests | Mac |
| Safari 2 | Test execution only via Selenium-RC | Start browser, run tests | Mac |
| Opera 9 | Test execution only via Selenium-RC | Start browser, run tests | Windows, Linux, Mac |
| Opera 8 | Test execution only via Selenium-RC | Start browser, run tests | Windows, Linux, Mac |
| Google Chrome | Test execution only via Selenium-RC(Windows) | Start browser, run tests | Windows |
| Others | Test execution only via Selenium-RC | Partial support possible** | As applicable |
* Tests developed on Firefox via Selenium-IDE can be executed on any other supported browser via a simple Selenium-RC command line.
** Selenium-RC server can start any executable, but depending on browser security settings there may be technical limitations that would limit certain features.
Flexibility and Extensibility??
You’ll find that Selenium is highly flexible. There are multiple ways in which one can add functionality to Selenium’s framework to customize test automation for one’s specific testing needs. This is, perhaps, Selenium’s strongest characteristic when compared with proprietary test automation tools and other open source solutions. Selenium-RC support for multiple programming and scripting languages allows the test writer to build any logic they need into their automated testing and to use a preferred programming or scripting language of one’s choice.
Selenium-IDE allows for the addition of user-defined “user-extensions” for creating additional commands customized to the user’s needs. Also, it is possible to re-configure how the Selenium-IDE generates its Selenium-RC code. This allows users to customize the generated code to fit in with their own test frameworks. Finally, Selenium is an Open Source project where code can be modified and enhancements can be submitted for contribution.
About this Book??
This reference documentation targets both new users of Selenium and those who have been using Selenium and are seeking additional knowledge. It introduces the novice to Selenium test automation. We do not assume the reader has experience in testing beyond the basics.
The experienced Selenium user will also find this reference valuable. It compiles in one place a set of useful Selenium techniques and best practices by drawing from the knowledge of multiple experienced Selenium QA professionals.
The remaining chapters of the reference present:
- Selenium Basics
- Introduces Selenium by describing how to select the Selenium component most appropriate for your testing tasks. Also provides a general description of Selenium commands and syntax. This section allows you to get a general feel for how Selenium approaches test automation and helps you decide where to begin.
- Selenium-IDE
- Teaches how to build test cases using the Selenium Integrated Development Environment. This chapter also describes useful techniques for making your scripts more readable when interpreting defects caught by your Selenium tests. We explain how your test script can be “exported” to the programming language of your choice. Finally, this section describes some configurations available for extending and customizing how the Selenium-IDE supports test case development.
- Selenium Commands
- Describes a subset of the most useful Selenium commands in detail. This chapter shows what types of actions, verifications and assertions can be made against a web application.
- Selenium-RC
- Explains how to develop an automated test program using the Selenium-RC API. Many examples are presented in both a programming language and a scripting language. Also, the installation and setup of Selenium-RC is covered here. The various modes, or configurations, that Selenium-RC supports are described, along with their trade-offs and limitations. Architecture diagrams are provided to help illustrate these points. A number of solutions to problems which are often difficult for the new user are described in this chapter. This includes handling Security Certificates, https requests, pop-ups, and the opening of new windows.
- Test Design Considerations
- Presents many useful techniques for using Selenium efficiently. This includes scripting techniques and programming techniques for use with Selenium-RC. We cover examples of source code showing how to report defects in the application under test. We also cover techniques commonly asked about in the user forums such as how to implement data-driven tests (tests where one can vary the data between different test passes).
- Selenium-Grid
- This chapter is not yet developed.
- User extensions
- Presents all the information required for easily extending Selenium.
The Documentation Team??
The Original Authors??
- Dave Hunt
- Paul Grandjean
- Santiago Suarez Ordonez
- Tarun Kumar
The original authors who kickstarted this document are listed in alphabetical order. Each of us contributed significantly by taking a leadership role in specific areas. Each chapter originally had a primary author who kicked off the intial writing, but in the end, each of us made significant contributions to each chapter throughout the project.
Current Authors??
- Mary Ann May-Pumphrey
- Peter Newhook
In addition to the original team members who are still involved (May ‘09), Mary Ann, and Peter have recently made major contributions. Their reviewing and editorial contributions proved invaluable. Mary Ann is actively writing new subsections and has provided editorial assistance throughout the document. Peter has provided assistance with restructuring our most difficult chapter and has provided valuable advice on topics to include. Their enthusiasm and dedication has been incredibly helpful. We hope they continue to be involved.
Acknowledgements??
A huge special thanks goes to Patrick Lightbody. As an administrator of the SeleniumHQ website, his support has been invaluable. Patrick has helped us understand the Selenium community–our audience. He also set us up with everything we needed on the SeleniumHQ website for developing and releasing this user’s guide. His enthusiasm and encouragement definitely helped drive this project. Also thanks goes to Andras Hatvani for his advice on publishing solutions, and to Amit Kumar for participating in our discussions and for assisting with reviewing the document.
And of course, we must recognize the Selenium Developers. They have truly designed an amazing tool. Without the vision of the original designers, and the continued efforts of the current developers, we would not have such a great tool to pass on to you, the reader.
