As we move away from the Monolithic architecture, we need to understand that the processes that used to work for us in the Monolithic application development also need to move along. During the development of the Monolithic application, we used to work with the testing strategies such as unit testing, which aimed to cover the functionality of the individual methods inside an application, followed by integration testing, which is used to cover the fact that these methods operate correctly with each other.

Inside the microservices architecture, things get a little bit complicated. We now have small services where each service is supposed to perform a specific functionality. These services indeed need to interact with each other over the network to produce any meaningful output for the business use case that might be there. But things do not end here. Each of these microservices are composed of several individual methods and interfaces that it needs to work correctly. This makes the case of testing the microservices an interesting one, because now, we not only need to perform the unit testing of the individual components of the microservices and the interaction between them, but we also need to test if the microservices are able to operate correctly with each other.

This asks for a more elaborate testing of the application, with several different techniques. Let's take a look at these techniques to understand them better.