Testing any application enables developers to ensure that everything is functioning as intended and that they are going to offer a flawless user experience. Application testing allows developers to check whether their application complies with UI, performance, and functional requirements. Various techniques can be used to evaluate web-based apps. Many open-source developers have merged these testing techniques into reusable libraries.
Many testing frameworks and libraries in the open-source community can be used for testing. One such well-liked and simple-to-use library among Java developers is Jest. No matter how complex the web application is, developers can develop its user interface with Jest. Several libraries are available for testing the Jest application. The top 10 Jest testing libraries and extensions for Java developers are highlighted in this post to help developers with testing. However, let’s first define Jest and discuss its features before moving on.
Developers gain access to an excellent toolset through Jest, which is centrally located, well-maintained, well-organized, and flexible to meet the needs of developers. Another superb feature is that much of its functionality is not dependent on third-party tools.
Both front-end and back-end application testing have significantly benefited from the popularity of Jest, which makes testing delightful. Its many additional features, such as a test runner, an integrated mocking library, an assertion library, a CLI tool that enables running only certain tests that fit a pattern, and excellent support for various mocking strategies, turn it into a framework rather than merely a library. Jest is used by several large organizations, including Twitter, Instagram, and Pinterest, for React testing.
It is most frequently used for unit testing and is readily expanded to include other integration tests. Among the numerous kinds of automated testing for applications, unit testing is frequently mentioned as being the most crucial. By breaking the application into smaller, completely isolated pieces, unit tests are primarily used to validate the application. Unit tests also guarantee to deliver more output than expected.
simple to set up
Setting up Jest is simple because it doesn’t need any configuration or setup. As a result, installing Jest as a prerequisite for a project requires no or very little modification to begin writing tests and delivering them.
When executing tests, isolation is a crucial characteristic. It guarantees that two distinct tests cannot interfere with one another’s operation or affect one another’s test findings. To reduce runtime, Jest tests are executed concurrently within their process. This implies that they are unable to interfere with other tests.
Performance and speed
The jest framework operates quickly. It effectively and promptly executes all of the test cases without any difficulties. The tests can be run in parallel against various setups, and by running those tests first, which takes more time, it can save a lot of time.
Powerful mocking support
Mocking is a method for separating numerous test cases; this separation is accomplished by exchanging the dependencies with objects that can be monitored and controlled. In Jest, mocking often entails changing fake functions for dependencies. All sorts of mocking, including timing mocking, functional mocking, and mocking specific API (Application Programming Interface) calls, are supported by Jest.
Support snapshot testing
Testing of snapshots is possible with Jest. For front-end testing, snapshots are a crucial feature. Snapshot testing is excellent for comparing the sequencing values of many other frameworks as well as for React Native and React applications. The snapshots enable matching with the saved snapshot and verifying for matching functionality. It requires updating the snapshot file to change the user interface.
For smaller applications without complex assertions or testing logic, Mocha provides a lightweight and easy-to-use solution. Developers may plug in and out most of the supporting libraries and tools in their chain, and it gives them full control over how and with which tools to test the code. Assertions, spies, and mocks are not supported by Mocha, but these features can be added through add-ons or plug-ins.
It includes testing the user interface’s response and visibility across a variety of devices with various resolutions. Previously, frameworks like Angular have been utilized via the CLI tool. When testing an application, many developers that utilize the Angular CLI love to use Jasmine. To test the Jest application, developers typically combine it with Babel and Enzyme.
Jasmine is used when a project needs to be integrated with external libraries and is extremely large. Keep in mind that Jasmine requires third-party tools and does not allow snapshot tests, code coverage tools, or parallelization.
The Jest component can be tested by developers without the need to install anything using an enzyme, which is a testing utility rather than a testing framework. It is one of the most popular frameworks created and maintained by Airbnb. To test the Jest application, it may be integrated simply with other frameworks like Jest, Mocha, etc. React or Chai can be utilized to make its assertions.
The enzyme can access objects, locate elements, interact with elements, simulate events, and render components so that testing its results is simpler. Developers may test Jest components without difficulty using Enzyme’s testing framework because it regularly syncs with Jest’s testing framework. Along with React, Mocha, and Karma or other frameworks, additional Jest testing libraries also use the enzyme.
Other characteristics include good plugin support, usage of shallow rendering, and manipulation of DOM elements, traverse, and even pretending to be a runtime element.
Kent C. Dodds created the React-testing-library, which is supported by an active community of developers. It makes component testing simple and provides user behavior for implementation details in tests.
This package, like enzyme, is a complete collection of React DOM testing tools with a focus on simulating actual user actions and workflows. The React testing library is used by organizations like Graphy, Ze Delivery, Commercetools, and Page Builder. It utilizes test-utils and react-dom as extensions of the former.
Cypress is an extremely quick end-to-end testing framework that makes it possible to write tests without using any other testing frameworks. Without the requirement for driver binaries, it operates flawlessly in Chrome, Firefox, and Edge. Because automated code and application code run on the same platform, full control over the application under test is provided.
When new code is deployed, Cypress’s control panel notifies users of possible distinctions and allows them to monitor the status of the tests. Time travel with snapshots, video and screenshot capture, automatic waiting, built-in parallelization, load balancing for simple debugging, and many more are just a few of the remarkable features offered by Cypress.
The Chrome Development Team created Puppeteer, a headless Chromium Node library. It offers DevTools protocol API for controlling Chrome or Chromium. Developers may launch Chrome, move across pages, get buttons, and click on them using the given API. In addition to this, Puppeteer is capable of generating screenshots and PDF files of web pages as well as automating tasks like form submissions and keyboard inputs. To test an application from beginning to end, it can be integrated with Jest.
Each testing framework and library has strengths and weaknesses of its own. The key to getting the greatest result, whether it’s a unit test or an end-to-end test, is selecting and integrating the correct testing framework, like Jest, with the right assertion libraries. While updating, extending, and modifying the code, it aids in the creation of a flexible and adaptable workflow.
It is important to highlight that regardless of the testing framework or library that developers opt for, it is essential to perform Jest tests on a cloud platform like LambdaTest. It offers real devices and browsers to guarantee that all the conditions experienced by real users are taken into consideration during testing.
LambdaTest is an AI-powered test orchestration and test execution platform that enables users to conduct comprehensive testing online using more than 3000 real devices, browsers, and operating systems combinations. For a seamless testing experience, this platform supports all of the major automation testing frameworks and CI-CD tools.
LambdaTest’s ability to track, analyze, and improve Jest app performance simplifies Jest monitoring. Additionally, by leveraging the parallel testing feature of LambdaTest, testers can run numerous tests concurrently.
In conclusion, Jest is a testing framework that is quick, and simple to install and set up. It was created by Facebook and is used by many developers to test all React-based projects and applications. The above-mentioned Jest testing libraries make it simple to quickly test the Jest web application.