I confess that at your title I was on the verge of blowing my moderators whistle and suggesting strongly that you read the half dozen other threads. But, it looks as if you have and are after some more specific advice on different areas.
Firstly, if you are dead-set on becoming a TP, then aero-eng then RAAF is almost certainly your best route. If you get an offer from the RAAF, try talking to them about deferred entry or sponsorship whilst you do the degree. 3 years of Aero + 3 years of gliding, and you're far more likely to pass military flight training anyway. And yes, Aerobatic experience will help you pass your military training.
Secondly, what does a TP do in the day job? Well certain parts of it are fairly standard, going in early for met-brief, checking the notams, and doing a certain amount of "CT", that is general flying to stay a safe and high-ability pilot.
But the main job of testing involves a lot more than just flying. Working in conjunction with an FTE (Flight Test Engineer) - or more likely within a large team of TPs and FTEs, the testing task falls like this:-
- Identify what we're testing, understand it fully
- Plan how it's to be tested
- Analyse and account for all the associated safety risks.
- Plan the specifics of the testing, including crewing, test cards, telemetry use, recording equipment.
- Go and fly it.
- Debrief the sortie(s),extract automated data from the aircraft.
- Work out what it all meant, write a report about it.
- Often, stand up in front of senior management, and explain it all in words of no more than 2 syllables.
The tasks above are shared between TP and FTE, but as a general rule, the FTE will concentrate on the data, technical planning, and reporting issues; the TP will concentrate on the flight safety and flying issues. In the report writing side, a TP will write most of the handling stuff, and the FTE will do most of the performance stuff and graph plotting. (Most FTEs are actually quite accomplished aircrew, and you'll be flying with them in a multi-crew environment and relying upon each other a lot, even in single seaters where the FTE will be there electronically as likely as not).
Speaking as an FTE who became a TP, both are great jobs.
Good luck,
G