Implementing unit tests for the account microservice

A copy of the source code for Chapter 7 can be found in the Ch12 folder of this book’s GitHub repository. This chapter will demonstrate how to test different microservices. We’ll start with the account microservice.

Create a new folder at the same level as the src folder and name it tests. Our main focus here is to test the src/services/account.js file. It contains the main logic and the required business rules that are implemented in our application.

Next, create a file called accountservice.test.mjs under the tests folder. Why the .mjs extension? This extension is used in Node.js projects to indicate that a JavaScript file should be treated as an ECMAScript (ES) module. This distinction is important because JavaScript supports two module systems: CommonJS and ES modules. Each has different syntax and behaviors. ES modules use import and export syntax. By using .mjs, Node.js can unambiguously determine that the...