start work on improving testing

[jGaboardi]

• start supplemental testing schema
  • [x] rename (and keep for now) test_fastpair.py --> test_fastpair_pre_010.py
  • [x] initialize test_fastpair.py for breaking out updated and fleshed out tests
• review current testing helper
  • [x] add type hinting
  • [x] DRY for robustness
• add more as we think of it