What Is Selenium?
Selenium is a set of open-source tools that automates web browsers with specific browser bindings. It’s largely used for web application testing but not limited to it. Selenium supports numerous programming languages (C#, Java, JavaScript, Ruby, Python, PHP), testing frameworks, and third-party libraries. Also, Selenium can be used for screen scraping.
Types of Testing You Can Automate with Selenium
Selenium uses its own toolbox to run tests across different browser instances. It suits for:
- Compatibility testing.
- Regression testing.
- Integration testing.
- API testing.
- System testsing.
- End-to-end testing.
- Performance testing.
Actually, any test you can run in a browser can be run with Selenium. You just need to learn to set it up 😉
Understanding Selenium Architecture
Each piece of the Selenium suite caters for a different testing need. The tool has three main components (considering that Remote Control and WebDriver have been merged), each with a different approach to automated testing .
Selenium WebDriver
Usually, when we talk about Selenium, we mean Selenium WebDriver – a tool for automating web app testing. WebDriver interacts with a browser directly. That’s what differentiates it from Remote Control: the latter needs a separate app to launch. A QA specialist commands WebDriver to interact with certain elements, and the browser responds with information about values and statuses of web elements, which are later recorded to the script.
Selenium IDE
IDE stands for Integrated Development Environment. It is available as a Firefox and Chrome extension that quickly generates tests through the record and playback functionality. Selenium IDE is perfect for prototyping tasks. To be fair, half of QA engineers reject this record/run tool, while the other half celebrate it. However, for teams that find Selenium WebDriver too high of an entry point, Selenium IDE with some plugins on top may be a possible solution.
Selenium Grid
This is a tool that allows you to run parallel tests on multiple browsers, machines, and operating systems. When used in large production environments, Selenium Grid is just a time-saver. Let’s say you need to run 100 tests. With this tool, you can set up four virtual or physical machines. So, it’ll take you about one-fourth of the time you would spend running all the scripts on a single device.
Also, you can use Selenium Grid to test an app in different browsers simultaneously: one machine would be running tests in Firefox, while the other would work in Chrome.
How to Choose the Right Selenium Tool?
As Selenium evolved, the mentioned tools have changed – and merged, in some cases. Knowing what each tool can be used for is a starting point for better understanding of Selenium testing. But how do you know which one to use?
From project to project, you’ll have to cope with different requirements. The specifics of each product (or its particular features) defines what functionality for AT you’ll need, and correspondingly what tool will work best for this case.
In short:
- Selenium WebDriver works perfectly for browser-based regression testing, allowing you to run scripts in multiple environments simultaneously.
- Selenium IDE is great for end-to-end testing. The highlights are instant feedback and opportunity to reuse test case logic in multiple scripts.
- Selenium Grid is the best pick for when you want to distribute scripts across several machines or manage different browser configurations with minimum effort.
Selenium has very detailed guides and a large user community, so you won’t have problems figuring out the details of WebDriver, IDE, or Grid.
Pros of Using Selenium
How does good old Selenium manage to stay at the top of the list of best tools with dozens of excellent AT solutions appearing on the market every year? Let’s take a look at its advantages.
- Cost-free
For sure, Selenium isn’t the only automated testing tool on the market. However, it’s the only free-of-charge solution that can compete with paid products. The open-source status of Selenium makes it a low entry point for many teams. - Easy to integrate with Agile, DevOps, CI/CD tools
The essence of Selenium falls perfectly into the main principles behind Agile, DevOps, and CI/CD. Selenium is portable across platforms and easily integrates with numerous solutions, such as Jenkins, TestNG, Maven, SauceLabs, QMetry, etc. It provides an unmatched flexibility. - Huge range of browsers and scripting languages
Ten programming languages and a number of browsers (Google Chrome 12+, Firefox 3+, Opera 11.5, Safari 5.1+) are at your service. Moreover, Selenium is the only mainstream tool compatible with Linux. - Large library of plugins and extensions
Selenium has an extensive selection of add-ons, plug-ins, bindings, and extensions to broaden its core functionality. You can just google “Selenium plugins for tool name” and find a solution for easy integration with your favorite tool.
Cons of Using Selenium
As a rule, every software product comes with a couple of pain points. And unfortunately, Selenium is not an exception. Here are some its drawbacks:
- Steep learning curve
Selenium WebDriver doesn’t support codeless testing, which is a widely discussed trend. Meanwhile, Selenium IDE offers no-code functionality with certain limitations. Long story short, those looking for a smart automation tool should look elsewhere. - Only used for web-based apps
We’d say it’s more of a limitation rather than a disadvantage, but still: you can’t automate desktop app testing with Selenium since it can’t recognize objects in desktop applications. - No automatic image verification
Image verification is one of the tasks that saves you much time when automated. Selenium doesn’t offer this feature, so you will need to find another software program. - No reporting capabilities
QA engineers, developers, and project managers need access to testing results. In an ideal scenario, they receive a report featuring detailed descriptions, screenshots/screencasts, and charts. The lack of automatic reporting is one of the biggest drawbacks in Selenium. In practice, however, teams rarely consider it a disadvantage. Integration with Extent Reporting, TestNG, JUnit and other frameworks solves this problem momentarily.
Wrapping Up
Selenium has a few aces up its sleeve: fast delivery, flexibility, and easy integration with various tools. Investing time in exploring the Selenium and its capabilities will set you up with a solid foundation in test automation. Long story short, Selenium testing is the base. So even if it is not the tool the team you are to join uses, getting familiar with Selenium is a must for AQA beginners.
