Unit Testing Tools for Angular and React Applications

Unit Testing

Unit testing when correctly performed on any project results in minimal bugs cropping out of the final output, even before starting the QA process. During a bug fix or attending a change request, changes to the code are imminent, and even for minor changes in the code, the developer has to manually unit test the application before passing on to QA team.

As features increase, release after release, sprint after sprint, the codebases grow exponentially. Manual Unit testing becomes a resource consuming and an error-prone task. It is high time to use the latest and effective automated Unit testing processes

In this article, let us have a quick peek on automated Unit testing for Angular and ReactJS projects using specific frameworks.

Angular – Karma & Jasmine

Karma is the default test runner for Angular applications. It provides complete flexibility; Karma can be tailored to suit varying needs to match the workflow. Karma includes the option to test the code on several browsers and even devices to ensure smooth operation of the code on the supported platforms.

Jasmine is a Behavior-Driven Development (BDD) framework which enables clean and understandable Syntax for writing test cases making the process easy. It does not depend upon any other JavaScript frameworks. Alongside Karma, Jasmine is the recommended testing framework for Angular, and it doesn’t require a DOM.

As mentioned earlier, when the application grows, the code and Unit test cases grow as well, keeping them well-structured and documented is vital, and Jasmine helps achieve them all. Angular projects by default have Karma and Jasmine for unit testing, as they both go very well. While Karma takes care of running the test cases on every browser and platforms configured, Jasmine ensures human-readable test cases.

React – Jest & Enzyme

Jest is a test runner, assertion and mocking library – basically, a JavaScript unit testing framework which is used by Facebook to test their services and React applications. Jest also provides something called, Snapshot testing – the ability to create a ‘snapshot’ of a component during runtime and compare it with a previously created ‘snapshot’. The test passes only if the two matches perfectly.

Enzyme is a JavaScript test utility for React applications that enables swift testing and interacting with elements. Enzyme is created by Airbnb. Both Jest and Enzyme are designed to test React applications; However, Jest works with any JavaScript applications like Angular and others, but Enzyme is solely for React. Jest, on its own, without Enzyme can render components and perform Snapshot testing as well. It is just that, Enzyme adds additional functionality to the testing. Jest and Enzyme are complementary tools that integrate well to provide effective test results.

Advantages of Unit Testing

  • Unit testing helps to add new features without breaking the existing functions.
  • Refactoring the code becomes easy, as it gives excellent control over the changes and bugs created of such changes in the existing code.
  • Test cases become proper documentation on their own.
  • Developers enjoy a boost in confidence about their code being bug-free.

Angular, React or any JS project – be it small or large, it is highly recommended to use automated Unit testing which can save vital resources in the longer run, resulting in bug-free output. Please contact us to learn more about unit testing tools and how to integrate the tools with your development process and deliver effective and efficient software.


  1. https://docs.angularjs.org/guide/unit-testing
  2. https://karma-runner.github.io
  3. https://jasmine.github.io/
  4. https://jestjs.io/
  5. https://airbnb.io/enzyme/