At risk of rehashing previous threads, verification (according to ISO12207) is ensuring the correct processes and standards are followed and that all requirements are traceable though the lifecycle, not the testing of actual requirements. Testing is a validation activity - you are validating the code against the requirement.
At the end of the day, your customer (via the contract or their specification) or your in house standards will define which you follow.
Or in the case of your thesis, YOU decide, and justify it.
This is the great thing about Standards - there are so many to choose from!
As an aside, the IEEE have fully adopted ISO/IEC 12207, and they are harmonising their standards with that Process Model (as are BSI in the UK) so I would expect the next iteration of IEEE 1012 to be more discerning.
With regarding the line between V and V, and where testing fits. ISO12207 s7.2.4 and 7.2.5.3.2 is the required paragraph, which details (and uses the word) Testing - in effect (within ISO12207) Testing is synonymous with Validation