Cypress.io and the Future of Web Testing

What is Cypress.io?

Cypress.io is an up-and-coming Web test automation framework. It is open source and written entirely in JavaScript. Unlike Selenium WebDriver tests that work outside the browser, Cypress works directly inside the browser. It enables developers to write front-end tests entirely in JavaScript, directly accessing everything within the browser. As a result, tests run much more quickly and reliably than Selenium-based tests.

Some nifty features include:

  • A rich yet simple API for interactions with automatic waiting
  • Mocha, Chai, and Sinon bundled in
  • A sleek dashboard with automatic reloads for Test-Driven Development
  • Easy debugging
  • Network traffic control for validation and mocking
  • Automatic screenshots and videos

Cypress was clearly developed for developers. It enables rapid test development with rapid feedback. The Cypress Test Runner is free, while the Cypress Dashboard Service (for better reporting and CI) will require a paid license.

How Do I Start Using Cypress?

I won’t post examples or instructions for using Cypress here. Please refer to the Cypress documentation for getting started and the tutorial video below. Make sure your machine is set up for JavaScript development.

Will Cypress Replace WebDriver?

TL;DR: No.

Cypress has its niche. It is ideal for small teams whose stacks are exclusively JavaScript and whose developers are responsible for all testing. However, WebDriver still has key advantages.

  1. While Selenium WebDriver supports nearly all major browsers, Cypress currently supports only one browser: Google Chrome. That’s a major limitation. Web apps do not work the same across browsers. Many industries (especially banking and finance) put strict controls on browser types and versions, too.
  2. Cypress is JavaScript only. Its website proudly touts its JavaScript purity like a badge of honor. However, that has downsides. First, all testing must happen inside the bubble of the browser, which makes parallel testing and system interactions much more difficult. Second, testers must essentially be developers, which may not work well for all teams. Third, other programming languages that may offer advantages for testing (like Python) cannot be used. Selenium WebDriver, on the other hand, has multiple language bindings and lets tests live outside the browser.
  3. Within the JavaScript ecosystem, Cypress is not the only all-in-one end-to-end framework. Protractor is more mature, more customizable, and easier to parallelize. It wraps Selenium WebDriver calls for simplification and safety in a similar way to how Cypress’s API is easy to use.
  4. The WebDriver standard is a W3C Recommendation. What does this mean? All major browsers have a vested interest in implementing the standard. Selenium is simply the most popular implementation of the standard. It’s not going away. Cypress, however, is just a cool project backed with commercial intent.

Further reading:

What Does Cypress Mean for the Future?

There are a few big takeaways.

  1. JavaScript is taking over the world. It was the most popular language on GitHub in 2017. JavaScript-only stacks like MEAN and MERN are increasingly popular. The demand for a complete JavaScript-only test framework like Cypress is further evidence.
  2. “Bundled” test frameworks are becoming popular. Historically, a test framework simply provided test structure, basic fixtures, and maybe an assertion library (like JUnit). Then, extra test packages became popular (like Selenium WebDriver, REST APIs, mocking, logging, etc.). Now, new frameworks like Cypress and Protractor aim to provide pre-canned recipes of all these pieces to simplify the setup.
  3. Many new test frameworks will likely be developer-centric. There is a trend in the software industry (especially with Agile) of eliminating traditional tester roles and putting testing work onto developers. The role of the “Software Engineer in Test” – a developer who builds test systems – is also on the rise. Test automation tools and frameworks will need to provide good developer experience (DX) to survive. Cypress is poised to ride that wave.
  4. WebDriver is not perfect. Cypress was developed in large part to address WebDriver’s shortcomings, namely the slowness, difficulty, and unreliability (though unreliability is often a result of poor implementation). Many developers don’t like to use Selenium WebDriver, and so there will be a constant itch to make something better. Cypress isn’t there yet, but it might get there one day.

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