In this chapter, we are going to develop an entire web application. The application itself is not a very realistic example, but should be realistic enough to demonstrate many kinds of testing practices and technologies. We are going to develop a calculator that can perform the pow operation. The calculator application is composed of the following components:
- A graphic user interface that is implemented using React, and fetches the result of the pow operation from a web service using an HTTP client
- A web service that is implemented using Node.js and Express.js, and finds the result of the pow operation using a small math library
The application's graphic user interface looks as follows:

We are going to define many different automated tasks using npm scripts. Each task uses different tools, and some tasks must take place before others. We could use...