I verified that running tests for installed 64-bit 3.9.0b1 on Win10 is somewhat a joke.  I got 22 failures.  Multiple tests failed on missing _testinternalcapi, and at least 1 on _xxtestfuzz.  Several tests had multiple failures and would need to be run individually and verbosely to see why.  For instance, test_itertools tries to run test.support.__init__.checksizeof 4 times, and the latter imports _testinternalcapi, resulting is 4 failures.

Release managers: I think installers should be run and the suite run with the result.  This is not the first time a file has been omitted.  One needed by IDLE was once omitted, I believe on Windows.  There is now a test that reads it, but is useless unless run.  (And I should add checks for all the other 'not .py' files.)

honglei: Thank you for both posts.  Next time, please remove the quoted message when replying by email.  Once posted on the web page, below the quoted message, the quote becomes redundant noise.