By instantiating the full microservice in-memory using in-memory test doubles and datastores it is possible to write component tests that do not touch the network whatsoever.

This can lead to faster test execution times and minimises the number of moving parts reducing build complexity.

However, it also means that the artifact being tested has to be altered for testing purposes to allow it to start up in a 'test' mode. Dependency injection frameworks can help to achieve this by wiring the application differently based on configuration provided at start-up time.