Review mock tests and potentially replace them

[masih]

Mock tests are useful but a pain whenever interfaces change or the internal interaction is altered. Review the mock tests for Participant and see what we can replace or remove.

[BigLep]

@masih : I have added this to MX: Priority and sequencing TBD since I'm assuming this isn't needed anytime between now and shortly after f3 activation. Let me know if that is wrong.