Selenium is a set of drivers that can be used to automate browsers. We can use them to manipulate browsers and page elements by, for example, clicking on a button or a link, filling up a form field, opening a specific URL, and so on. There are drivers for almost any browser—Android, Chrome, FireFox, Internet Explorer, Safari, and many more. Our favorite is PhantomJS, which is a headless browser that works without any UI. Running stories with it is faster than with traditional browsers, and we often use it to get fast feedback on the readiness of web applications. If it works as expected, we can proceed and try it out in all the different browsers and versions that our application is supposed to support.
More information about Selenium can be found at http://www.seleniumhq.org/, with the list of supported drivers at http://www.seleniumhq.org/projects/webdriver/.
While Selenium is great for automating browsers, it has its downsides, one of them being that it is operating at a very low-level. Clicking on a button, for example, is easy and can be accomplished with a single line of code:
selenium.click("myLink")
If the element with the ID myLink does not exist, Selenium will throw an exception and the test will fail. While we want our tests to fail when the expected element does not exist, in many cases it is not so simple. For example, our page might load dynamically with that element appearing only after an asynchronous request to the server got a response. For this reason, we might not only want to click on that element, but also wait until it is available, and fail only if a timeout is reached. While this can be done with Selenium, it is tedious and error prone. Besides, why would we do the work that is already done by others? Say hello to Selenide.
Selenide (http://selenide.org/) is a wrapper around Selenium WebDrivers with a more concise API, support for Ajax, selectors that use JQuery style, and so on. We'll use Selenide for all our Web steps, and you'll get more familiar with it soon.
Now, let us write some code.