Historically in the UK this would be the difference between B conditions and A conditions, there's a similar distinction in the SETP membership criteria:
B-conditions / test flight /experimental flight - "there's new information we don't have and are flying to obtain that information, most likely outside the existing cleared envelope in some way". This sort of flight testing also generally requires task specific risk assessments.
A-conditions / check flight / production test flight - "it's been built or modified to a known good standard, and are flying to confirm that, and are firmly within an existing cleared envelope". Generic operating risks apply, without special risk assessments.
The requirement for a flight test rating / authorisation is a whole separate kettle of fish. Under the coming EASA rules a "flight test rating" will be required for testing of aeroplanes above 2000kg, under what would have been UK B-conditions. Under 2000kg that won't be required. The FT rating will require 1000+ hours on class and an IR.
Historically the UK required a form (the AD458) to be submitted to the CAA which was basically a very short test flying CV, and on the basis of that personal approval was given. France and Germany had formal flight test ratings based upon a specific syllabus. The new EASA rules, reasonably pragmatically, work very like the UK's AD458 system, whilst "looking" at the end very like the French/German system from the outside.
(Military regulations are different, but the basic principles don't change.)
G