The English langage (well, only as used by some) is confusing, because of being too simplistic, not enough vocabulary : the reported sentence from mr Lowry can make a lot of people believe - and notably the airline pilots without University background - that the guy signing the tech log will become one day a Test Pilot, given the opportunity.
It should be stressed that an engineer is a mechanic, and not a Graduate Engineer (somebody with a couple of Masters or PhD in Engineering from difficult Universities, who could or couldn't not be very good in changing the tyres or unplugging the GPU after starting the engines)
You meet the graduate engineers in aircraft factories, and some from Flight Test department will work on a daily basis with Test Pilots, and some of them will therefore become FTE (Flight Test Engineers) through the appropriate channels. In some countries you even have a distinction between Flight Test Mechanics and Flight Test "engineers" - separate courses at the Test Pilot School, different diplomas, different backgrounds (which doesn't mean they don't work together after !)
Same for Test Pilots and Acceptance (or production) Pilots, either you ave the diploma, or you don't.
Same for Test Pilots, factories (not only in Aerospace) are full of people claiming to be Graduate Engineers, when they are technicians at best.
A couple of technical questions or homework will usually put the record straight...
Now I'm expecting the usual answer "who cares about the diploma, it's the value of the individual who comes first.." Typical political correctness, in times when any youngster downloading stuff with a laptop does claim to be a scientist...
My personal advice to anybody aspiring to a career in the area : go for the highest diploma first, associated with the highest qualifications, that will solve a lot of your job-searching tasks... otherwise, be prepared to be hired through graphology, group exercises, psycho interview, Zodiac signs, freemasonry, or even quotas for previously disadvantaged populations...)
As some people say, diplomas and qualifications are only for people who couldn't do otherwise !
A lot of issues are currently coming from EU bodies (EASA) trying to streamline the diplomas amongst 28 or so countries - and for diplomas related to flight test, only a handful of nations have a significant aircraft industry, and feel (or not !) the need to standardize it. For example Ireland with thousands of commercial pilots and the english langage like US or England, but without a related industry, will not care at least....