Testing test environments

It might become a little meta. I’m looking into a new project as staff-level test lead. The project is about building a kubernetes platform for environments. The construction team makes sure the platform services are established. User journeys around creating infrastructure components "Infrastructure as code" style. yeah! (finally)

My task is to lead the migration into the platform for 8 systems, with each their set of environments. So at least 24 individual migrations, given that each system has a at least a dev, test and prod environment.  

But what are the test cases for the migrations? Each system has their own business domain, but that is not the test scenarios we are looking for. Neither a classical functional regression suite. The test cases for the migration are all about testing environments as an object of test (CRUD-style), not a place of testing. Though we still need a test environment to test our test environment generation....