The hotel review application

In this section, we will add unit and integration testing to the hotel review application that was created in Create React App. This application lets you add reviews to a list of hotels and controls this data from an application context. The React Testing Library will be used to render React components to test assertions on these components.

Unit testing components

Unit testing is an important part of your application, since you want to know that your functions and components behave as expected, even when you make code changes. For this, we're going to use the React Testing Library, an open source testing package for React applications that was created by the React community. With the React Testing Library, you can test assertions – for example, whether the output of a function matches the value you expected.

To get started, we don't have to install anything; it's part of Create React App. If you look at the package.json...