Add proper coverage for SearchEntityMixin in test_entity.py

[oshtaier]

We have already provided coverage for 'common' scenario for ReadEntityMixin, UpdateEntityMixin and CreateEntityMixin, so it will be nice to have something similar for search functionality

[elyezer]

:+1:

[Ichimonji10]

To be clear, there are unit tests for the EntitySearchMixin in module tests.test_entity_mixins. I think what's being requested here are additional tests in tests.test_entities.

[oshtaier]

Right, to have pretty similar approach for all entities. And, of course, that task has low priority