Unit testing for microservices
In this section, we’ll focus on testing microservice-specific functionalities in NestJS, with particular attention to inter-service operations rather than the basic unit testing of APIs. If you need a refresher on the fundamentals of unit testing, please refer to Chapters 7 and 8. Here, we assume you’re already familiar with those basic concepts and are now diving deeper into testing for microservices.
Unit testing microservices involves testing individual units of functionality in isolation, including inter-service communication, which is a defining aspect of microservice architecture. In NestJS, microservices often communicate via events or messages passed through a message broker or a client proxy. This means we need to focus on mocking external services and ensuring the inter-service calls are properly handled and tested in isolation.
Let’s get started by testing the order creation flow.
