unittest and automatically firing off tests

[Tom Plunket]

I'm a long-time CppUnit TDDer and a relatively competent C++
coder...  I'm trying to make tests that automatically fire off
every time I run the test app, so I derive my test classes from
unittest.TestCase, build a bunch of tests in each one called
testSomething, and name the file test_<class_under_test>.py.
Finally, I have test.py implemented as such:

: import unittest
: import os
: 
: if __name__ == "__main__":
:     names = os.listdir('.')
:     tests = []
:     for name in names:
:         if name[:5] == "test_" and name[-3:] == os.extsep+"py":
:             modname = name[:-3]
:             tests.append(modname)
:     tests.sort()
: 
:     for test in tests:
:         try:
:             unittest.main(test)
:         except SystemExit:
:             pass
: 
:     s = raw_input("\n<Enter> to continue.\n")
:     pass

Things I don't like about this?  You bet.

1) Why in the name of all that is holy does unittest.main() throw
   regardless of tests passing?

2) Why can't I readily pass a list of tests to unittest.main()? 
   (I mean, besides the fact that it's not implemented; was this
   a concious ommision?)

3) I feel like I should automatically batch up tests and fire
   them off to unittest.run() or something similar.  Is this as
   straight-forward and easy, and could I batch them all into one
   mega-suite?  Are there any reasons why I wouldn't want to do
   that?

Thanks.

-tom!