Unit tests ensure that your code functions as expected under multiple circumstances.There are a couple of reasons to consider writing unit tests for your applications: Unit tests allow us to test the different functions in our applications. Unit tests are pieces of code that examine if a function performs as expected when separated from other components of your application. In this article, we will look at how to use Mocha for testing, Chai for assertions, and Sinon for mocks, spies, and stubs. JavaScript and Node.js have many testing and assertion libraries, like Jest, Jasmine, Qunit, and Mocha. If the code is properly tested, another engineer can confidently add new code or modify existing code with the expectation that the new changes will not break other features or, at the very least, will not cause side effects to other features. Properly written tests ensure that new features do not introduce changes that break the application.Īn engineer maintaining a codebase might not necessarily be the same engineer that wrote the initial code. Tests help document the core features of an application. Node.js unit testing using Mocha, Chai, and SinonĮditor’s note: This article was last updated on 5 January 2023 to ensure that all information is compatible with the latest versions of Mocha, Chai, and Sinon at the time of writing. Godwin Ekuma Follow I learn so that I can solve problems.

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