Some vendors may only 'test' as far as getting the compiler to produce something without errors. So, first thing an end-user/consumer/enterprise customer can do when encountering a new platform is to run the platform through https://uefi.org/testtools, in particular the FWTS/Firmware Test Suite and SCT/ACPI Self-Certification Test, and hold the vendor accountable. Chances are the vendor already has a member on the board of the Unified Extensible Firmware Interface Forum.