There’s a new kid on the block for open source test automation tools, and everyone’s talking about how Cypress may be an alternative to Selenium.
But while some have posed that Cypress signals the end of an era, we’re not so sure that Selenium is going anywhere anytime soon.
To better understand the similarities and differences between these two tools, let’s take a better look at what they both do.
Selenium
Selenium WebDriver is the open source automation tool we all know and love. With a history starting from the humble beginnings of IDE and transforming into Selenium 2.0 a.k.a. Selenium WebDriver, Selenium has become a foundation of many modern software teams’ test automation toolkits.
Most are familiar with Selenium’s use -- it makes direct calls to the browser using each browser’s native support for automation. By writing a script in Selenese using the compatible programming languages, you can run tests that work as if you were driving the browser yourself.
While the learning curve can be steep for Selenium and requires the knowledge of at least one programming language, it has a vast community of active users and even boasts an annual user conference.
One of the foundations of Selenium is the ability to test on the most popular browsers, making it essential to cross-browser testing.
As testing with Selenium has grown in popularity, it’s not only become a basis of many automation strategies but has also become an integral part of many third-party tools such as CrossBrowserTesting. Once you know how to use Selenium, you can use these cloud testing tools to access thousands of browsers and leverage parallel testing to cut down on testing time.
Cypress
So how is Cypress different from Selenium, and how is it the same?
First, Cypress is said to have an easier onboarding than Selenium, where all you need to do is install the .exe to get up and running sine all the drivers and dependencies are automatically installed. With Selenium, on the other hand, you need to spend a little more time getting everything up and running.
One of the advantages of Selenium is that it supports most of the major programming languages including Java, Perl PHP, Python, Ruby, and C#, so if your team is already using one of those languages, Cypress may not be ideal since it only supports JavaScript.
In addition, since Cypress tests are written using Mocha and Chai, the syntax echoes what most Javascript users understand. This means that if you work with Javascript, it will be especially easy to start using Cypress. However, if you’re more familiar with another language, it will be fairly complex.
Cypress almost acts as a “freemium” model. Similiar to Selenium which is entirely open sourced unless you integrate with a paid tool, you can also add to Cypress's core capabilities by leveraging the paid dashboard which includes a test runner that allows you to easily debug tests with DOM snapshots and includes video storage for private projects.
Selenium and Cypress differ in the way of their architecture, as well. Selenium is made up of bindings, or libraries, and the WebDriver, which controls the browsers. These two components work through the JSON network.
Alternatively, while Cypress is used for UI testing, it uses its own unique DOM manipulation and runs directly in the browser with no network communication. Cypress is often cited as a developer-friendly test automation tool for this reason since this often causes frustrations for them in Selenium.
Having a different architecture on top of an Electron app also allows Cypress to be so close to the web application under test that we can do things that you can't do in Selenium such as stubbing DOM APIs.
One of the biggest gaps between Selenium and Cypress is that while Selenium runs against different browsers, as mentioned before, Cypress only supports Chrome. Selenium’s browser support is often integral to those who use it, making Cypress severely lacking in the area of cross-browser testing.
For software teams that find importance in checking their website on multiple browsers instead of just leaving their code up to chance, finding their way around this deficiency could prove challenging to Cypress users.
Cypress vs Selenium
Cypress and Selenium serve a similar purpose that is achieved in two different ways.
Selenium is a library but requires a unit testing framework or a runner plus an assertions library to build out its capabilities. Cypress provides a robust, complete framework for running automated tests but takes some of the freedom out of Selenium by confining the user to specific frameworks and languages.
If you don’t know what you’re doing when it comes to building out a test automation framework, Cypress may be a good option.
Another thing to keep in mind is that if you look at how Cypress is built, it is largely a unit testing tool that is will fit best in Javascript-focused development teams. Once you stray from these details and your team decides to experiment with other methods of test automation, you’ll find that Selenium can better accommodate those growing pains.
As a tool made by developers for developers, it’s less a replacement for Selenium and more so a way to introduce developers to test automation.
Like most instances when it comes to test automation, the tool you pick and the method you follow will largely depend on what your team decides and what works best for your organization. However, the notion that Selenium is on its last legs is misled.
If you’re still confused as to the differences between Cypress and Selenium, Automation Rhapsody provides a really great breakdown of how each performs in different categories.