Considering the nature of NextGen, do we need to write new tests in tempest or tempest plugins?

OpenShift has its own tests, OpenStack as well (tempest, tempest plugins), is there something in between which should be tested and is not covered by either OpenShift or OpenStack testing frameworks?

DoD:

• we know the answer to the above question
• if the answer is yes but the tests won't live in tempest, tempest-like framework, it doesn't concern this ticket nor the epic this ticket is under.