Full Stack JavaScript Strategies

Chapter 7. Backend Testing

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At this point in the project, you’ve got quite a bit of code. There are services, controllers, and integrations. While you and the team will do your best to not introduce code regressions (where previously working functionality is broken from an unrelated change), that will happen at some point, and it’s normal as the code grows. That’s why you write tests for the major functionality of the app.

On the backend, you’ll test for things like errors being called in the correct scenarios, data being returned in the correct format, and the correct methods being called with the correct parameters. Writing unit tests like these will help keep you from making regressions, understand the way the code should work, and make the code maintainable because you are writing more concise, modular code.

In this chapter, we’ll cover:

• Trade-offs between having tests and not having them

• How to write tests using Jest

• The importance of mock data

Regardless of whether you are starting ...