10 Best Practices for Writing E2E Tests With Cypress

Testing has become an important part of software development, and for a good reason. Writing software of any complexity can be a nasty process, and it only gets worse as teams grow and more people work on the same codebase. This challenge is exacerbated in front-end development. There are so many moving pieces that creating unit and functional tests may not ensure that the program is working properly. A unit test, for example, can’t confirm that a specific user flow isn’t causing problems. End-to-end testing enables you to simulate user behavior on your app and ensure it functions properly. Creating e2e tests is a no-brainer if you’re writing production-grade web applications.

This blog will look at how to utilize Cypress to develop meaningful e2e tests on the front end. We will concentrate on Cypress’s definition, comparison with Selenium, and best practices to follow to achieve optimal results

What Is Cypress?

Cypress is a front-end testing tool designed for today’s web. This tool solves the common problems that developers and QA engineers have while testing contemporary apps, such as synchronization difficulties and test inconsistencies due to parts that aren’t visible or accessible. It’s written in Node.js and available as an npm module. It utilizes JavaScript to write tests since it is based on Node.js. However, 90% of the code can be done using Cypress’s built-in commands, which are simple to grasp.

It also comes packaged with jQuery (Javascript Library) and inherits several of jQuery’s techniques for UI component identification and manipulation and event handling, Ajax, and CSS animation.

Why Is Cypress Testing Important?

Following are the points that help in determining the importance of Cypress testing.

First and foremost, Cypress is a more general automation tool than other automation solutions. It’s developed in Javascript and uses Node.js to run in the browser. It’s based on Mocha and Chai. This means it may be used to test nearly any website, not only those built in Javascript. As a result, it’s a perfect alternative if you wish to test apps created in, such as the newest React, Angular, Vue, Elm, and so on.
Because it is built on Node.js, all you have to do to install Cypress is run npm install Cypress. For a typical installation, all dependencies are already present. You won’t need any extra libraries, testing engines, servers, drivers, or wrappers, and you won’t have to configure anything. Cypress is a highly accessible tool for QA engineers, and it not only makes it easy for JS developers to start automated testing.
Debugging is also fairly simple with Cypress. Cypress offers native access to every item inside your program, which simplifies error investigation. While the tests are running in the browser, you may use Chrome DevTools to debug your application. That’s not all, however. When a test fails, Cypress provides a clear and understandable error message and advice for how to improve the implementation.

Cypress allows you to create a variety of tests, including end-to-end tests, integration tests, and even unit tests, but I wouldn’t say it’s a tool built specifically for any of them. The actual strength of this structure comes from combining them. You have the same control and power to check the behavior of functions and server replies in Cypress as you have in unit testing. One of the main advantages of using Cypress for end-to-end testing, in my perspective, is the ability to submit and inspect backend requests. As a result, you won’t need to use any additional libraries for API testing since you will be able to submit queries on the fly while testing your frontend app.
Cypress e2e tests are quick to run. You don’t need to implement any extra waits, either implicit or explicit since it waits for the DOM to load automatically. Cypress tracks everything that occurs in your app in real-time, including when the page loads and when components transmit events. As a result, Cypress may wait for items to appear or animations to finish and for various requests to be sent or returned. The bulk of Cypress’ operations are executed inside the browser; therefore, there is no network latency.

Comparison Between Selenium And Cypress

Cypress is a front-end testing tool for the current web based on JavaScript. It aims to alleviate developers and QA engineers’ difficulties while testing an application. It is a more developer-friendly tool that functions directly in the browser and employs a unique DOM manipulation method. Cypress also offers a one-of-a-kind interactive test runner that performs all instructions. At the time of test execution, the Cypress framework takes snapshots. This enables developers to hover over a command in the Command Log to view precisely what occurred at that point.

Unlike Selenium, there is no need to include implicit or explicit wait instructions in test scripts. Cypress waits for orders and assertions automatically. Developers and Qas may use Spies, Clocks, and Stubs to check and manage the behavior of server replies, functions, and timers. In Cypress, the automated scrolling checks that an element is visible before taking any action. Previously, Cypress only allowed Chrome testing, but now it supports Edge and Firefox browsers, thanks to recent revisions. Cypress executes instructions in real-time as they are written by the programmer, delivering visible feedback as they run. It also comes well-loaded with documentation.

Selenium, an open-source tool, has been a top option among testers for more than a decade. As may use the Selenium WebDriver library and a language-specific framework to automate test cases for the specified browser. Before automating your browser, you must first download the browser-specific driver.

Cypress is not just an alternative for Selenium, but it is also an excellent tool for teaching developers about test automation. This is why Cypress is one of the world’s fastest-growing automation tools. On the other hand, Selenium is a more general-purpose tool aimed at a larger audience.

Best Practices for Writing E2E Tests With Cypress

Following are the best practices to follow while writing ESE tests with Cypress:

Test Design- Before beginning the implementation, create a basic test design and share with the team.
Independent Testing- Automated tests must execute in isolation, without requiring the execution of another test to produce a state in the application under test. The findings of one test should not be influenced by the failure of another. In addition, parallelizing independent testing is easy.
Test Data– Try not to keep test data in the script. Always keep test data in a secure area. We have the ability to keep test data on cypress.env.json and fixtures files in Cypress. To obtain Environment Configurations, use getters

Page Elements- Page with element data-testid recorded. UI must be designed and implemented as the data-testids are being defined during the development process.
DOM Element Status- Verify the DOM element status using assertions and timeouts. It uses this to see whether the appropriate DOM element matches a set of criteria within a specific amount of time. For each option, Cypress includes a default set of timeouts, which you may alter to a shorter or longer number depending on product performance and test execution environment [Cypress timeouts]. In the event of a network interruption, define time outs with a buffer time. On the other hand, this buffer period must be acceptable; otherwise, we will be unable to notice any product or environmental performance difficulties. Instead of waiting, use timeouts.
Programmatic Authentication- Logging in through the graphical user interface as a pre-condition for all tests is inefficient (in terms of execution time) and makes the tests reliant on one another, which is poor practice. For example, a blocked login button caused by an HTML issue should not cause a whole test suite to fail. You may make testing quicker and more independent by adding tools to log in programmatically.

State Creation Techniques – By implementing such mechanisms, we can assure that tests are totally detached from one another, that we don’t require complicated abstractions like Page Objects, and that tests are quick and to-the-point. API calls for producing resources, task-based database connectivity, and operating system-level scripting are examples of these techniques.
Do Not Test External Apps – Relying on Google’s GUI login or a third-party API for your tests might make them unstable, since changes to these services (which you don’t control) could break your tests, even if everything “on your side” is OK. You may use a smoke-test suite or contract tests to confirm that such services are compatible with your application.
Insufficient Or Excessive Testing – End-to-end tests are not basically unit tests. It is worth noting that more than one assertion per test saves time due to the expense of executing them. Extensive testing, on the other hand, should be avoided. Perhaps they are evaluating a variety of unrelated items that might be divided down into smaller tests.

Name of the test script – The name of the test script should be in lower case and the user narrative should be highlighted in the script name.

You will have quick and robust tests that your team trusts and helps to maintain and improve if you follow these best practices. You can leverage platforms like LambdaTest with which you can run end-to-end tests on a Cypress test execution cloud that is also lightning fast. Built for scalability, a dependable, scalable, secure, and high-performing test execution platform, with LambdaTest, you can test on more than 40 different browsers and versions, including headless browsers.