/me nods...

Thank you for your excellent suggestion.   Naturally, I desire to drive this (at least on the outermost level) strictly from a shell command, and to minimize isolate the influences of “browser versions.”   Yet I understand, of course, that this is not 100% achievable.

I fully realize that this kind of testing-scenario is greatly complicated by the fact that Flash is client-side software, with several different not-quite compatible versions of the client-side engine.   (Meh... the preceding sentence is called, “tact” “diplomacy.”)   Not to mention the fact that browsers are “client-side software” too, as are the client-side operating systems.   I know that I’m going to make compromises, so to speak.   “To test this experiment, I must be partly inside the experiment.”   I desire for these compromises to be the best and most well-considered set of compromises ... which is why I am humbly petitioning here.

It is important to emphasize that my scenario is regression testing.   The Flash code works, and it is not my immediate objective to verify that it does so.   Rather, I seek to automate tests which will detect if it ever ceases to do so.   I want to barrage it with tests, each of which has known expected outcomes.   If the system falls out of compliance, I want to know.