Test / RF Connection Method
One of the most critical differences between 5G/NR and legacy LTE in terms of RF environment can be summarized as follows :
Considering all of these factors, we may reach an important conclusion : Conductive testing (Direct connection between UE and Test Equipment with RF Cable) would not be acceptable in most of the testing. It means we need to do most of the tesing in OTA (Over The Air) connection.
Then a couple of questions as follows would pop up right away in your mind :
The firm/official answer to these question is supposed to come out by 3GPP, but I would introduce a well-described idea proposed by Intel in R4-165050(Ref ) as follows.
 3GPP RAN4 #80 R4-165050 : Testability considerations for NR