The application started earlier is a web application that does not have a graphical interface (i.e., a frontend). For this reason, it can only be tested by sending HTTP requests using a client such as Postman. We will not show how to use Postman to connect to a web application backend.

In the Postman application, we can create the two types of applications we want to test: • GET  shows us the list of books in the library • POST  adds a book to the library.

The steps to accomplish this are outlined below. First, once we have opened the Postman application, press the + button, as can be seen in the image below (the button is circled in red):

• a text file containing the executed commands