jest VS Sinon.JS

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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.

Jest is a well-regarded JavaScript testing framework primarily designed for React applications, although its utility extends to projects using Babel, JavaScript, Node, Angular, and Vue. Created by Facebook, Jest emphasizes ensuring the correctness of JavaScript codebases. It allows developers to write tests with a familiar, feature-rich API, making the testing process swift and enjoyable​​.

If you are using a mocking library, such as sinon, jest-mock, or ts-mockito, make sure that it is compatible with Jest. You may need to install additional packages or configure them in your configuration file. For example, to use sinon with Jest, you can install the sinon-jest package and add the following to your configuration file:

Mocha is a test runner, Chai is an assertion library, Sinon is a mocking library, this normally the combination you would need to use if you choose mocha, but there are others.

Instead, use pure functions + dependency inject your stubs (e.g. parameter to function). Also note, no need for Sinon or some other test double library. JavaScript is so good nowadays to easily make objects/classes/functions or any combination thereof on the fly that are terse.

I've had some good experiences with Ava + Sinon. I've personally disliked Jest because it seemed to do some weird trickery in the background that prevented me from using ES modules.

🤖 You can use the Mocha testing framework with the Chai assertion library to write tests for your Express controller. You can also use the Sinon library to mock the database calls. This will allow you to test the controller without actually making a call to the database. You can also use the SuperTest library to make HTTP requests to the controller and test the response.

You can use sinon js to create a mock version of your http library (axios) that responds with the data you’re expecting.

Assertions are the checkpoints of our test block that confirm if an automated test has passed or failed. Cypress bundles the Chai, jQuery, and Sinon.JS libraries for assertions. They check the desired, expected application in which the test is running. A complete listing of assertions can be found in the documentation here.

ES module is basically a "class" that you inject dependencies into through imports. And for tests you just use something like sinon to swap module dependencies for mocks.

You can use a tool like sinon to pass in your own function instead of the real moment library. From there you can write tests that ensure moment was invoked appropriately.

Let's configure tests with mocha, chai and sinon on Typescript in a few steps.