It's even worse, many tests fail with 1 to 3 memory blocks on x86 Gentoo Refleaks 3.x... but then pass when run again.

I created bpo-31227 "regrtest: reseed random with the same seed before running a test file" which might help (or not?) this issue.

http://buildbot.python.org/all/builders/x86%20Gentoo%20Refleaks%203.x/builds/62

test_sys leaked [1, 1, 1] memory blocks, sum=3
test_robotparser leaked [1, 1, 1] memory blocks, sum=3
test_nntplib leaked [1, 1, 1] memory blocks, sum=3
test_tools leaked [3, 2, 1] memory blocks, sum=6
test_fork1 leaked [1, 1, 1] memory blocks, sum=3
test_poll leaked [1, 1, 1] memory blocks, sum=3
test_asyncio leaked [2, 1, 1] memory blocks, sum=4

Re-running failed tests in verbose mode
Re-running test 'test_sys' in verbose mode
Re-running test 'test_robotparser' in verbose mode
Re-running test 'test_nntplib' in verbose mode
Re-running test 'test_tools' in verbose mode
test_tools leaked [1, 3, 1] memory blocks, sum=5
Re-running test 'test_fork1' in verbose mode
Re-running test 'test_poll' in verbose mode
Re-running test 'test_asyncio' in verbose mode