In the field of computer science, a faster feedback loop is a contributor to the agile development process. It enables a responsive development process to iterate and improve the software quality rapidly. Parallel testing is a software testing technology, able to run multiple test procedures simultaneously on different environments (Devices and Browsers). This testing process speeds up the total testing chronology to customise the execution time and accelerate the faster feedback process. Jest is a well-known testing framework, associated with JavaScript. It was developed by Facebook to test JavaScript projects, specifically for React applications. Jest provides versatile feature sets, including automated test detection, parallel testing, and code coverage summarization.

In LambdaTest, we focus on the loops to gain a faster feedback process with Jest by using parallel testing. In this article today, we are going to discuss the execution of the parallel testing process with Jest to achieve faster feedback loops.

What Are the Possible Parallel Test Execution Processes Available in The Market?

As per the modern landscape of the evolving configuration of automation testing tools, it is necessary to know about the various parallel test executors available in the market.  In LambdaTest, we are familiar with using the below-mentioned tools with the Jest also.

TestNG:

It is a testing framework only for Java which supports the texting process in a parallel way. In this framework, the testing process may contain different threads and multiple machines.

JUnit 5:

It is an updated version of the JUnit testing framework only for Java. It also supports the parallel execution process related to annotations and custom configuration processes.

Selenium Grid:

Selenium Grid allows the developers to execute the testing process on various machines and new age browsers. It supports the WebDriver tests, to perform the parallel testing.

TestCafe:

TestCafe empowers developers to test Web applications concurrently on multiple browsers.

Cypress:

It is an end-to-end web testing frame, which performs parallel testing with the help of some third-party solutions.

RSpec-Parallel:

A Ruby gem testing process for the Ruby ecosystem. This tool also provides the parallel testing process only for the JavaScript developed process.

pytest-xdist:

The framework is a Python-based testing process. It opens a path for parallel testing on multiple processing units and hosts.

With these testing processes, Jest has taken a great role to accelerate the parallel processes with the JavaScript model to get faster feedback from the existing loops present in a system.

A Detailed View of Jest (Application, deployment and powerful features, etc.)

Nowadays, Jest has become a widespread testing framework, designed to test JavaScript projects specifically for React applications. It is a simple and efficient process with convenient usage and powerful features:

Installation and Setup: Jest can be installed easily by using npm or yarn. After completing the installation process, users need to run the jest — init command to configure the JavaScript file for the process customization.

Testing Framework: Including ES 6 and JSX, Jest can test any JavaScript code easily. For modern projects, Jest has been updated as per the React development standards.

Test Writing: Jest has an interactive API process which makes the test process so fluent.

Snapshot Testing Process: This feature allows the user to capture the output of the component. Further, it will be saved as snapshots in a data structure.

Mock Process to Test the Capabilities: It offers robust mock capabilities to isolate the code from external dependencies.

Coverage Reporting: It is a larger book to save the data of the runnable parts of the entire code. It also marks the bugs and faulty parts, which need to be updated.

Parallel Test Execution: A by default out-of-the-box method, which concurrently runs these.

Test Watch Mode: Facebook’s Jest has an automated powerful feature that detects the need for code changes with instant feedback.

A Sync Testing Support: It has built-in support to test the asynchronous code and callbacks.

Customise the Configuration: It is a configuration system to create custom aspects based on test environment, behaviour, and patterns.

Expect Library: Jest has an expert library model with vast matchers to assert the present values.

Setup the Test Environment: Jest allows you to create a setup file before any test execution with global variables.

Overall, Jest has simplified the JavaScript testing methods with the most comprehensive and advanced toolsets. Gradually, it became the fastest text execution process with the above-mentioned features.

What Are the Actual Processes to Get the Faster Feedback Loops?

In a software development process, it is a crucial thing to achieve faster feedback from the process. We need to jot down and optimise the related processes for the software development life cycle. Here are some key steps mentioned below –

Automated testing process: It is a strategy that includes unit testing, test integration and user-end tests. The automated testing executes in a quick and frequent manner with the rapid feedback by marking the issues at an early stage in the development process.

CI process: The continuous integration is an automated approach which reciprocates multiple times in a day. Each step triggers a build schema and allows the developers to receive quick feedback on the immunity of the base code.

Parallel test process: This process is able to handle multiple machines at a certain time simultaneously. It reduces the execution time and provides faster feedback on test results.

Isolate the test: Treat the current tests as the isolated one to make the process of maintenance easier and independent.

Data management after the test: Data generation and management can be handled by the snapshot feature to run the tests in a quick manner.

Review the codes: Encourage the developers to schedule the review process for the codes. It helps them to find the issues in the initial stage and update the code further as per the report.

Develop and deploy continuously: We, here at LambdaTest, follow the continuous development and deployment process to maintain the code safety of an automated process. This process helps us to cut down the feedback on the loops from the end-users.

Monitoring: With the comprehensive monitoring and logging, LambdaTest tries to detect the real-time errors present in the production environment.

Feedback method: The communication between the developers and users needs to be established to get an insight about the prior improvements and bug fixes.

Flag features: Here developers need to use the flags before the future releases. It empowers them to release the developed application for a small number of users to get the test results.

Optimization: Last and foremost step for a development. These steps involve with automation process and tools to process the further improvements to expedite the outcome.

How The Parallel Test Execution Process Can Be Performed with Jest to get the Faster Feedback Loops?

Jest is a well-known JavaScript testing framework that delivers parallel testing facilities by default. By executing the parallel test process, we can significantly cut down the execution time of a process. The less time consumption leads to faster feedback loops during the project development.  Here are some steps mentioned below:

Enable the parallel execution process by configuring the Jest- Jest supports an out-of-the-box approach to execute the parallel test. It is a process that is enabled by default, users don’t need to activate it additionally.

Developers just need to confirm that the test language is independent. It means they should have the ability to run without making any connection with each other.

Conduct the Test Suites- Test Suites are just like a container that encompasses the collection of test cases by preparing their report status. Each Test Suite needs to focus on the specific testing module with proper isolation. The isolation is an essential module for the parallel execution process in Jest.

Avoid the shared state: When the projected test results become parallel in manner, it can lead to the whole process to an unpredictable result. It is a need to set up a suitable testing environment and run the cleaning process after every process. To manage setup and cleaning Jest have some functions like “bedoreAll”, “beforeEach”, etc.

Develop and define some isolation modules: In some cases, for the Jest test process, it is needed to develop some isolation strategies. If the process needs to access the database, developers should develop and define some testing ways to perform the concurrent execution bypassing the conflicts.

Run the Jest module as a Parallel option: –runInBand and –maxWorkers are those Jest test parallel functions that use the available numbers of CPUs to track the number of workers processed in the system. It can be run manually also.

Track the monitor performance: It is an essential process to monitor the performance and resource usage simultaneously. Depending on the possible complexities of the test procedures we can perform the parallel tests which leads to the degradation of the total performance. It is a balanced system between the process speed and resource allocation as per the Jest policy.

Real-life implementation of Jest:

Nowadays, Jest has become the most popular and adopted choice for many testing companies like LambdaTest. Here are some real-time examples of that –

Facebook: Jest was developed by Facebook as their essential testing framework for React applications. Facebook usually tests its front-end codes to sustain flawless services.

React: It is a React testing framework by default. Many React developers test their developed components on this.

Airbnb: It is a well-known online marketplace for testing the JavaScript codebase. They adopted the Jest platform to test various modules present in the application.

Twitter: Twitter has a Jest testing framework to test their front end. It can develop complex components with JavaScript libraries.

Shopify: It is another well-known e-commerce platform and a result of collaboration with Jest. It helps to maintain the quality of any other web applications by ensuring their test efficiency.

WhatsApp: WhatsApp is a Meta-owned texting platform that also implemented Jest procedures, depending on the JavaScript codebase for stability and identity.

Open-source libraries: There are so many Open-source libraries present in the market which allows Jest to test their frameworks.

Conclusion:

Today in this blog, we have tried to explain the future of the Jest with the parallel test execution to gain faster feedback loops. In this modern world, Jest’s popularity has made it a go-to choice for so many JavaScript developers and teams like LambdaTest. Its ability to handle individual tests and integration with snapshot testing made it a really powerful and versatile framework in the practical scenarios.  Here we have discussed the processes above with different scenarios related to the parallel test execution processes in a detailed manner with Jest to gain the faster feedback loops. Don’t forget to subscribe to our LambdaTest YouTube channel to access the complete playlist and stay updated with the latest content related to parallel tests and faster feedback loop processes with Jest platform.