test_*: converted to the new test harness. GvR note! test_signal.py
works interatively (i.e. when verbose=1) but does not work inside the
test harness. It must be a timing issue, but I haven't figured it out
yet.
I'm really not sure what the proper inputs are. I do flex the
function call though by passing in arguments of the proper type. I
don't try to exec the code object that gets returned!
