Guide to React Integration Testing

When working on a React project that involves integration with multiple external services and APIs, it is fundamental to conduct integrity testing of the software. This is essential to ensure a successful project that is free of errors and glitches when upgrading to the most recent version, without losing any vital features. Neglecting this testing may pose a risk of project failure, with unexpected results and malfunctioning components.

Establishing the suitable tests for React components can prove to be an arduous task, given the possibility of false positive and false negative results if errors occur in the testing process. Additionally, conducting integration testing for a React project can present a substantial obstacle, calling for strategic manoeuvres.

This guide furnishes detailed guidance on how to set up your project, write tests and run them efficiently during development.

To begin with, it is essential to comprehend what an integration test entails and how it distinguishes from unit testing and functional testing.

What is Integrity Testing?

Following unit testing, integration testing comes next in the software development life cycle. Its primary aim is to guarantee the seamless interaction of all individual software components. Integration testing’s goal is to identify any problems that may arise as a result of integrating various modules.

Before proceeding to integration testing, unit tests are conducted on all software modules. Different sections of a larger software application are developed by individual developers or coders. During the integration process, the communication between modules is vetted for compliance with standards.

Constituting an indispensable aspect of software testing, integration testing assures that all components operate cohesively within the larger system. To ensure the smooth flow of data, it is imperative to ascertain that all parts or modules can function independently. Integration testing is utilised for this purpose, confirming the compatibility of all software elements.

Integrity tests are tailored specifically for websites that incorporate React technology. These tests proffer an all-inclusive evaluation of the user experience, minimising the time and resources required for end-to-end testing. As such, they serve as an efficacious technique for appraising your application’s performance.

Outlined below are three common types of tests:

  • Assembly Line:

    validates the accuracy of a single line of code at a time, which fails to provide a comprehensive assessment.
  • Despite its need for greater investments of time and resources for creation and execution, end-to-end (E2E) testing necessitates the utilisation of automation technologies like Selenium and Cypress to simulate genuine user actions on a website. This approach enables the creation of a user experience that is difficult to distinguish from the real thing.
  • Integration testing exists between end-to-end testing and unit testing on the testing continuum. Its purpose is to verify the proper operation of all components of an application when they operate in conjunction. To assist in this process, various tools are available, including jsDOM, which imitates browser APIs with minimal overhead, as well as mocking tools, which simulate external APIs. Both of these tools are integrated into the Jest testing framework to expedite integration testing.

React’s Integration Testing: Its Significance

The three most common types of testing are unit testing, integration testing, and end-to-end testing.

Integration testing encompasses a range of techniques that are not unduly time-consuming to apply due to functionalities like testing component interoperability and simulating actual situations, such as HTTP requests. This approach to testing is efficient and fosters trust in the development team’s capabilities. Incorporating integration testing at the commencement of the project may reduce the need for unit tests significantly.

As a result, it is necessary to devote time to generate integration tests. Nonetheless, it is feasible to produce valuable unit tests and full-stack tests.

Allocating most of your resources to creating integration tests could be a prudent choice because they offer the most effective method of maximising your time and energy usage.

Typical Techniques for Testing React Applications

Integration testing is an integral component of the software development process, and four primary approaches can be employed: big-bang testing, top-down testing, bottom-up testing, and hybrid/sandwich testing. In this piece, we will examine the benefits and drawbacks of each technique to help you determine the most suitable one for your development project.

Dynamic Experiments

The Big Bang Integration Testing approach involves integrating and testing all components as one entity comprehensively. This technique involves joining all components simultaneously, resulting in a fully functional system. The Big Bang approach stands out due to its all-inclusive integration and testing methods.

Although this approach is effective, it is possible that the absence of monitoring of the interfaces between the system’s various components may make it challenging to detect any problems that arise. As a result, it is crucial to implement measures to verify that the interfaces are being monitored to expedite the identification of the source of any issues.


  • This technique is ideal for testing systems with low scale.
  • Identifying bugs in these systems enables you to expedite your application releases with minimal effort.


  • Tracking the source of errors in situations where numerous modules are integrated into one may be difficult.
  • Big-bang testing requires a significant amount of time to produce outcomes when deployed in a large system with numerous components.
  • The duration of an integration test can vary drastically. To begin the testing process, all modules must be operational, allowing developers more time to correct any mistakes. As a result, the overall testing period may be prolonged.

Top-Down Approach Analysis

With the top-down approach, testing is conducted in an orderly manner, beginning with the most complex modules and concluding with the simplest ones. After testing each component separately, the entire system is constructed to assess its efficiency.


  • It is much easier to identify issues and determine their origins.
  • When testing, giving priority to the examination of the most critical units yields the most effective outcomes in detecting critical design issues.
  • Preliminary prototypes can be developed.


  • When only the fundamental modules are examined, the testing may be inadequate or overlook crucial details.
  • The presence of too many test types slows down the testing procedure.

Reverse Engineering

Contrary to top-down integration testing, bottom-up integration testing starts by inspecting the individual modules at the system’s lowest level and then gradually moves to more intricate modules. If all system components are accessible for testing at the same time, this approach can be employed.


  • Isolating and diagnosing faults are simplified.
  • Issues can be located and resolved more quickly when no modules are awaiting testing.


  • If all modules are not adequately tested, there may be a delay in delivering the final product.
  • Even with a comprehensive testing process, some bugs may remain undetected until the end of the process, as testers usually only review mission-critical modules at the end. This gives developers limited time to identify and rectify any overlooked issues.
  • Testing a software system consisting of numerous small components may pose a challenge.
  • This technique cannot be utilized to create a functional prototype.

Analyzing Sandwich and Hybrid Designs

Integration testing is a procedure of validating the accurate operation of individual software components when they are combined. Two aspects are involved in this process: testing the communication between them and testing the interfaces between components. Two approaches, i.e., top-down or bottom-up approach, can be employed to conduct integration testing for comprehensive coverage of the components.

Sandwich testing is a hybrid integration testing approach that incorporates components of both top-down and bottom-up testing techniques.

Sandwich testing presents several advantages to testers, enabling them to execute tests with enhanced precision and efficiency. This testing method is a hybrid system that utilizes both stubs and drivers.


  • Software testing is crucial for long-term projects such as operating systems, and the best approach is to utilize it.


  • Software testing is an expensive and time-consuming process.
  • This testing technique requires a high degree of precision and skill.

What are the recommended practices for conducting Integration tests?

Listed below are the phases of an integration test:

  • Developing a testing strategy.
  • Devising the testing plan, including generating test cases and scripts.
  • Tests are performed once modules or units have been integrated.
  • Rectification of errors after they have been identified.
  • Validating restored functionalities following issue resolution.
  • This process will be repeated until all issues are resolved.

A Guide to Jest and the React Testing Library

In Simple Terms, What is the Meaning of “Jest”?

Jest is a testing tool designed specifically for JavaScript and TypeScript that can be effectively used with the integration of React framework.

The testing methodology of this framework ensures the precision of any JavaScript library. Its user-friendly API facilitates quick and easy test writing, while its extensive documentation and straightforward setup make it highly adaptable to your requirements.

The philosophy behind this framework is simplicity, which is reflected in its minimalistic design and robust Application Programming Interface (API) for individual testing, mock testing, comparison, test coverage, and other functionalities.

A Quick Look at the React Testing Library

The React Testing Library is a JavaScript testing utility that aids in testing React components. By emulating user interactions with individual components, it verifies that the User Interface (UI) is performing as expected, providing developers with the assurance that their application is operating as intended.

Developed by Kent C. Dodds, the React Testing Library is a lightweight testing framework that acts as an alternative to the Enzyme component. This library offers several extra utilities to the react-dom and react-dom/test-utils packages, enabling a more comprehensive testing process.

As it is a DOM testing library, the React Testing Library utilises actual DOM elements in its testing methods, rather than solely depending on the displayed React components.

With its emphasis on effective testing practices and relative ease of implementation, you can begin using it right away.

First Step in Working with the Example Application

To construct the React application, we will employ npm, which necessitates the usage of node.js. Therefore, make certain that you have installed node package manager.

To create a directory that includes a subdirectory named ‘src’ for storing all the user interface-related files of the application in one location, allowing for easier compilation of the necessary files, run the following command in the terminal:

To initiate this project, we need to install and configure the essential libraries, which can be streamlined and made more convenient with the appropriate command. Utilising this command simplifies the deployment and launch of a React application.

While Jest and the React testing framework are effective tools, they do not possess the capability to conduct end-to-end testing. This kind of testing entails testing the entire application to examine how the individual components interact. As a result, neither Jest nor the React testing framework support this type of testing.

Comprehending progressively complicated applications while encountering numerous obstacles can be discouraging. However, there are various useful tools available for conducting end-to-end testing of React-based applications, and automated testing may provide improved and quicker outcomes.

By the conclusion of this guide, you should have the confidence to utilise React for integrated testing. You should have a clearer understanding of how to effectively integrate your created tests into the broader React testing framework. With this knowledge and expertise, you can competently test all features without any hesitation.

Integration testing evaluates how the individual components function and work together as part of a cohesive whole. We may also perform regression testing to increase our confidence and ensure that any changes we make do not cause any issues.

Integration testing facilitates an evaluation of the entire application stack, guaranteeing proper functionality of each component and effective coordination between all components. Such testing is critical for verifying the application’s overall functionality, not just the performance of isolated components.

To guarantee the smooth and proper operation of all application components, integration testing is indispensable. Integration tests can be built using any framework, and most frameworks offer support for visual testing of React applications.


  1. Does Jest have a substantial edge in integration testing?

    When it comes to integration testing, Jest – a free and open-source test framework developed by Facebook – offers a highly efficient solution. This command-line tool, which operates similarly to Jasmine and Mocha, enables comprehensive testing of the entire technology stack, rather than merely the user interface. Utilising fake functions is a breeze and requires no setup at all. Furthermore, snapshot testing -which allows testers to verify the results of rendering components -is a valuable and highly effective feature.
  2. What is the optimal tool for testing React applications?

    A wide array of open-source testing tools are available for React applications, each with its own unique features. Consequently, software engineers need to take time to carefully consider which tool to implement. Jest and Enzyme are the two most widely used tools for testing React components.

    With the appropriate instruments, both unit testing and system testing can be performed. Several of the most commonly employed testing tools, which have been recommended by both developers and testers, include:
    • Jest
    • Mocha
    • Jasmine
    • Enzyme
    • Chai
    • CypressIO
  3. Which is superior: Jest or Mocha?

    For testing React projects, it is advisable to use either Mocha or Jest for optimal results. Although Jest takes a more simplified approach to testing, Mocha offers some additional features that can prove beneficial.

    Jest is an ideal selection for those seeking a straightforward testing experience that does not require learning a new syntax. On the other hand, if you require more advanced features and the latest enhancements, Mocha is the preferred option.
  4. I’m uncertain about the difference between Jest and the React testing libraries.

    Jest, as a test runner, is the go-to option for testers who require a tool to locate, execute, and assess the outcome of testing. Meanwhile, React Testing Library enables the testing of React components through the provision of a virtual DOM.

    Jest is a remarkable tool in its own right, and many developers find it to be highly effective. However, React testing offers the flexibility to work with any other testing library.
  5. Is Enzyme necessary for Jest to function?

    Both Jest and Enzyme are popular choices for testing React applications. Although Jest is compatible with any testing framework, Enzyme is currently only compatible with the React testing framework.

    If Enzyme has not been installed, Jest can still be used effectively for testing purposes. Jest boasts a broad range of outstanding features, but combining it with Enzyme will greatly enhance its capabilities. While it is feasible to use Enzyme without Jest, it must be paired with another test runner to function properly. In other words, Enzyme cannot execute tests without a test runner.

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