threading._DummyThread.__init__():  document obscure new code.

test_threading.test_foreign_thread():  new test does a basic check that
"foreign" threads can using the threading module, and that they create
a _DummyThread instance in at least one use case.  This isn't a very
good test, since a thread created by thread.start_new_thread() isn't
particularly "foreign".
2 files changed