It works when one uses the right dotted name ;-)

D:\Python\dev\py33\PCbuild>python_d -m unittest -v idlelib.idle_test.test_calltips.Test_get_entity.test_bad_entity
test_bad_entity (idlelib.idle_test.test_calltips.Test_get_entity) ... ok
----------------------------------------------------------------------
Ran 1 test in 0.000s
OK

idlelib.idle_test.test_calltips.Test_get_entity works too. I did not know about these options; I added them to @README as part of revising it. I also added verbosity and exit args to all if-name unittest.main calls, which are ignored anyway when either unittest or regrtest import the modules.  New patch uploaded.

With this additional confirmation, I am about ready to commit -- when I feel fresh and ready to monitor the buildbots. But I notice that the non-executable @README has 7 ways to run all or part of the suite, most of which have appeared in this issue. Even with history retrieval, I am tired of retyping to test changes. I should have started with an executable test suite test (.bat or .py using subproccess for the command lines). Then I could have just added the two cases above and re-run after today's edit. I may do this first.