[IronPython] Misleading test runner output /all VS /test:name_of_test

[Daniel D.]

Hi.

Please, help me wrap my head around this issue. Wanted to run
unittests to see what areas need to be addressed.

This is the tail of

...
Languages\IronPython\IronPython\cpy test_univnewlines_cpy
                    PASSED    6.7633868
Languages\IronPython\IronPython\cpy test_weakref_cpy
                    FAILED    14.8568497
Languages\IronPython\IronPython\cpy test_zipfile_cpy
                    DISABLED  0
Languages\IronPython\IronPython\cpy test_zipfile64_cpy
                    DISABLED  0
Languages\IronPython\IronPython\modules modules_io_related_ipy
                    PASSED    15.1468663
Failed test summary:
test_pyc_ipy
modules_system_related_ipy
test_subprocess_cpy
test_weakref_cpy
Total time: 1743.824741 seconds

Immediately after that ran the "failing" test_subprocess_cpy
individually and got a passing grade:

C:\work\ironlang>Test\TestRunner\TestRunner\bin\Debug\TestRunner.exe
Test\IronPython.tests /test:test_subprocess_cpy /verbose
Languages\IronPython\IronPython\cpy test_subprocess_cpy
                    PASSED    343.3856406
Total time: 343.428643 seconds

I guess we can expect some variation in outcome there, due to random
load effects on pipe throughput between subprocess and calling parent
code, and I will check for that. Besides the randomness of conditions,
are there variations in settings between /all and /test:name_of_test
that would cause different test outcomes?

Daniel.