bpo-34279: regrtest consider that skipped tests are ran

[vstinner]

bpo-34279, bpo-35412: support.run_unittest() no longer raise
TestDidNotRun if the test result contains skipped tests. The
exception is now only raised if no test have been run and no test
have been skipped.

[vstinner]

With this change:

$ ./python -m test test_dtrace -v
== CPython 3.8.0a0 (heads/platform_macos9:720f137b5e, Dec 12 2018, 16:30:08) [GCC 8.2.1 20181105 (Red Hat 8.2.1-5)]
== Linux-4.19.3-300.fc29.x86_64-x86_64-with-glibc2.28 little-endian
== cwd: /home/vstinner/prog/python/master/build/test_python_6308
== CPU count: 8
== encodings: locale=UTF-8, FS=utf-8
Run tests sequentially
0:00:00 load avg: 0.58 [1/1] test_dtrace
skipped 'dtrace(1) failed: /usr/bin/dtrace invalid option -q\nUsage /usr/bin/dtrace [--help] [-h | -G] [-C [-I<Path>]] -s File.d [-o <File>]'
skipped 'dtrace(1) failed: /usr/bin/dtrace invalid option -q\nUsage /usr/bin/dtrace [--help] [-h | -G] [-C [-I<Path>]] -s File.d [-o <File>]'
skipped "stap(1) failed: [Errno 2] No such file or directory: 'stap'"
skipped "stap(1) failed: [Errno 2] No such file or directory: 'stap'"

----------------------------------------------------------------------

Ran 0 tests in 0.123s

OK (skipped=4)

== Tests result: SUCCESS ==

1 test OK.

Total duration: 249 ms
Tests result: SUCCESS

Without this change:

$ ./python -m test test_dtrace -v
== CPython 3.8.0a0 (heads/platform_macos9:720f137b5e, Dec 12 2018, 16:30:08) [GCC 8.2.1 20181105 (Red Hat 8.2.1-5)]
== Linux-4.19.3-300.fc29.x86_64-x86_64-with-glibc2.28 little-endian
== cwd: /home/vstinner/prog/python/master/build/test_python_6411
== CPU count: 8
== encodings: locale=UTF-8, FS=utf-8
Run tests sequentially
0:00:00 load avg: 0.38 [1/1] test_dtrace
skipped 'dtrace(1) failed: /usr/bin/dtrace invalid option -q\nUsage /usr/bin/dtrace [--help] [-h | -G] [-C [-I<Path>]] -s File.d [-o <File>]'
skipped 'dtrace(1) failed: /usr/bin/dtrace invalid option -q\nUsage /usr/bin/dtrace [--help] [-h | -G] [-C [-I<Path>]] -s File.d [-o <File>]'
skipped "stap(1) failed: [Errno 2] No such file or directory: 'stap'"
skipped "stap(1) failed: [Errno 2] No such file or directory: 'stap'"

----------------------------------------------------------------------

Ran 0 tests in 0.124s

OK (skipped=4)
test_dtrace run no tests

== Tests result: NO TEST RUN ==

1 test run no tests:
    test_dtrace

Total duration: 250 ms
Tests result: NO TEST RUN

[miss-islington]

Thanks @vstinner for the PR 🌮🎉.. I'm working now to backport this PR to: 2.7, 3.6, 3.7.
🐍🍒⛏🤖

[bedevere-bot]

GH-11155 is a backport of this pull request to the 3.7 branch.

[bedevere-bot]

GH-11156 is a backport of this pull request to the 3.6 branch.

[miss-islington]

Sorry, @vstinner, I could not cleanly backport this to 2.7 due to a conflict.
Please backport using cherry_picker on command line.
cherry_picker 3a8f4fef4a4dd0e4a800545468eef9542e126181 2.7

[bedevere-bot]

GH-11158 is a backport of this pull request to the 2.7 branch.