I can't speak to any agency except PADI, but here is a synopsis of what is covered in the drysuit course:
- an overview of different types of drysuits: advantages, disadvantages, materials, etc.
- how to adjust a drysuit for proper fit.
- what to wear under a drysuit.
- overview of how to use the drysuit (PADI teaches using the suit for buoyancy control u/w and only using the BC on the surface).
-weighting systems & how to use them.
- proper maintenance of the drysuit.
- confined water training where the student determines proper weighting, how to use the drysuit (including righting yourself from a feet-first ascent, how to overcome a stuck inflator valve, etc.). Mastery of these skills is required before a student can progress to open water.
- two open water dives are required for certification. During these dives the student must demonstrate they can perform all the necessary skills (neutral buoyancy such as hovering & fin pivot, etc.).
A drysuit is NOT a passive piece of equipment like a pair of fins that you just put on & go... it requires proper training to use it safely & effectively.
If you have any further questions about the course, please feel free to email me.
As to the other comment about selling a drysuit to someone without checking to see if they were drysuit certified: just as you can buy any other piece of dive equipment without being certified, you can also buy a drysuit.
~SubMariner~