testing-library-docs VS jest

Testing Library provides a great set of accessibility-focused tools to locating elements when writing tests. It was created by Kent C Dodds, one of my longtime favorite educators on front-end and testing topics. Since the initial release in 2018 as "React Testing Library", it's grown in popularity beyond its React component testing roots. It now has plugins for all major test runners and JavaScript frameworks, and in 2022 some of its patterns were adopted in Playwright's test runner as the recommended way to locate elements.

Probably Enzyme was the first to popularize component testing in React by doing shallow rendering and expecting some things to be there in the React component tree. Then React Testing library came and took component testing to a whole new level.

18.react-testing-library

Jest has long been my favorite got to test runner when it comes to UI unit and integration testing. With tools like React Testing Library (Testing Library framework for React) you get the benefit of very easy to write and maintain tests, as well as a quick and efficient way to run our tests.

I'm writing an intergration test with Testing Library where I'm on a boards dashboard area and a user can click a button to create an item on the board. I'm using an intercepting route to do show the popup form. Once finished the user goes back to their area and should see the created board.

This article uses Jest and React Testing Library. It's okay if you want to use other libraries, the fundamentals in this article will help you there as well.

This is the idea behind Testing-Library from what I understand.

https://testing-library.com/

The Testing Library: The Testing Library offers guidance on best practices for testing user interfaces effectively, with a focus on user-centric testing.

There are great tools like Testing Library that render a single component in a single state and then programmatically inspect the resulting DOM. However, the salient details of the rendered HTML – like color, layout, and scale – are hard to express. So, the tests end up brittle (over-specified) or insufficient (under-specified).

There are several testing approaches you can take to ascertain the functionality of the auth API. One way would be to automate the testing using unit tests with tools like Jest and Supertest. Alternatively, you can make use of API clients like Postman or the Thunder Client VS Code extension to test the API.

GitHub | Website

Jest

you have selected a testing framework. In my case, it's Jest with Supertest

Jest, created and maintained by Facebook, is a JavaScript testing framework with a focus on simplicity. It is often recognized for its zero-configuration setup and seamless integration, especially with React applications, making it a favored choice for developers in both small-scale projects and large enterprise applications.

Jest (https://jestjs.io/)

console.error Jest encountered an unexpected token Jest failed to parse a file. This happens e.g. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is not configured to support such syntax. Out of the box Jest supports Babel, which will be used to transform your files into valid JS based on your Babel configuration. By default "node\_modules" folder is ignored by transformers. Here's what you can do: • If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/ecmascript-modules for how to enable it. • If you are trying to use TypeScript, see https://jestjs.io/docs/getting-started#using-typescript • To have some of your "node\_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config. • If you need a custom transformation specify a "transform" option in your config. • If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option. You'll find more details and examples of these config options in the docs: https://jestjs.io/docs/configuration For information about custom transformations, see: https://jestjs.io/docs/code-transformation

Note: I will be using Jest as testing framework throughout the examples.

We use Jest Framework for testing. Jest is not a dogma, and, of course, in its place can be any other test runner, such as Mocha or Ava. Let's focus on tests. I'll provide a short example because I don’t want to waste your time. You can find the full version here. It's crucial to read the comments in the code below. Let's go!

Jest has long been my favorite got to test runner when it comes to UI unit and integration testing. With tools like React Testing Library (Testing Library framework for React) you get the benefit of very easy to write and maintain tests, as well as a quick and efficient way to run our tests.