The most important way to learn how to test React components in the right way is by writing some code, and that is what we are going to do in this section.
The React documentation says that at Facebook they use Jest to test their components. However, React does not force you to use a particular test framework, and you can use your favorite one without any problems. To see Jest in action, we are going to create a project from scratch, installing all the dependencies and writing a component with some tests. It'll be fun!
The first thing to do is to move into a new folder and run the following:
npm init
Once package.json is created, we can start installing the dependencies, with the first one being the jest package itself:
npm install --save-dev jest
To tell npm that we want to use the jest command to run the tests, we have to add the following scripts to package.json:
"scripts": {
"build": "webpack",
"start...