Tests

1. Create and destroy DB
2. Get single OS, single device, single hypervisor
   Treat all as entity
   Get id, params, value for param, all values for param
8. Given OS, HV, get device driver. Also NULL HV, and also case with no driver. (no HV info, or HV info and no support)

3. Filter self-test
4. Get list of OS, Dev, HV filtered
5. Get two filtered lists, do list operations

6. Get unique values for OS, Dev, HV, and list of OS by relationships
7. Get hypervisor device types, and devices per type, with and without filter
9. Get preferred device for OS and all devices for OS given HV/not HV.
10. Get related OSes.