Although I paid dues for a PEng license for over 30 yrs as an EE, (with zero benefit) we never had sub-classifications for TE's even though I consider myself one after doing R&D for 10yrs then later Manufacturing, Design, Test, Management etc.
Now many jobs for TE's exist and no affiliations or associative Titles are needed.
Just relevant experience is needed in the technology being tested.
For example in 1983, Burroughs hired me as an HDD 5.25" specialist Test Engineer and I knew nothing about hard disk drives or the specialized test equipment. But I knew everything about the sub-circuits (servos, PLL, data separators, and high tech measurement methods common to many technologies)
Don't worry about affiliations, just look at job requirements and skills you are learning or can learn quickly.
Just remember a Test Engineer is invaluable because "if you cannot specify it or measure it, ** you cannot control it**.". Thus TE's learn or know what QA and Design Engineers must know to ensure a product will work. They know many software tools, hardware issues, EMI, statistics and how to use Object Oriented block diagrams to design quickly high level testers or. modify scripts to automate test vectors and work in both analog, digital, time and frequency domains whenever required. They also know how to demand Design Specs up front before designing a Test and how to document in a Heirarchichal Input, Process Output or HIPO method with categories for external stresses (environmental) and Functional requirements and have a good graphical or statistical skill to report the results.
Although "Software" Test Engineers need to know less about the hardware, it is helpful.