Define Unit Tests (Java)
You already have an existing Java Domain service, you want to include unit testing for that service.
You already have an existing Java Domain service, you want to include unit testing for that service.
You want to write unit tests without having access to all of the infrastructure which can be achieved by mocking which is described here in this How-To.
An External Entity is considered a proxy of an entity that is managed by another microservice. Normally, the external entity contains only the most important data that is regularly needed in the context of the aggregate to which the external entity belongs. Because of these specifics, it is handled differently than a usual Entity.