bpo-30822: Exclude tzdata from regrtest --all (#2775)

When running the test suite using --use=all / -u all, exclude tzdata
since it makes test_datetime too slow (15-20 min on some buildbots)
which then times out on some buildbots.

-u tzdata must now be enabled explicitly, -u tzdata or -u all,tzdata,
to run all test_datetime tests.

Fix also regrtest command line parser to allow passing -u
extralargefile to run test_zipfile64.

Travis CI: remove -tzdata. Replace -u all,-tzdata,-cpu with -u all,-cpu since tzdata is now excluded from -u all.

.travis.yml

@@ -62,7 +62,7 @@ matrix:
             ./venv/bin/python -m pip install -U coverage
       script:
         # Skip tests that re-run the entire test suite.
-        - ./venv/bin/python -m coverage run --pylib -m test -uall,-cpu,-tzdata -x test_multiprocessing_fork -x test_multiprocessing_forkserver -x test_multiprocessing_spawn
+        - ./venv/bin/python -m coverage run --pylib -m test -uall,-cpu -x test_multiprocessing_fork -x test_multiprocessing_forkserver -x test_multiprocessing_spawn
       after_script:  # Probably should be after_success once test suite updated to run under coverage.py.
         # Make the `coverage` command available to Codecov w/ a version of Python that can parse all source files.
         - source ./venv/bin/activate
@@ -95,7 +95,7 @@ script:
   # Only run on Linux as the check only needs to be run once.
   - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then ./python Tools/scripts/patchcheck.py --travis $TRAVIS_PULL_REQUEST; fi
   # `-r -w` implicitly provided through `make buildbottest`.
-  - make buildbottest TESTOPTS="-j4 -uall,-cpu,-tzdata"
+  - make buildbottest TESTOPTS="-j4 -uall,-cpu"
 
 notifications:
   email: false

Lib/test/libregrtest/__init__.py

@@ -1,5 +1,5 @@
 # We import importlib *ASAP* in order to test #15386
 import importlib
 
-from test.libregrtest.cmdline import _parse_args, RESOURCE_NAMES
+from test.libregrtest.cmdline import _parse_args, RESOURCE_NAMES, ALL_RESOURCES
 from test.libregrtest.main import main

Lib/test/libregrtest/cmdline.py

@@ -127,8 +127,17 @@ Pattern examples:
 """
 
 
-RESOURCE_NAMES = ('audio', 'curses', 'largefile', 'network',
-                  'decimal', 'cpu', 'subprocess', 'urlfetch', 'gui', 'tzdata')
+ALL_RESOURCES = ('audio', 'curses', 'largefile', 'network',
+                 'decimal', 'cpu', 'subprocess', 'urlfetch', 'gui')
+
+# Other resources excluded from --use=all:
+#
+# - extralagefile (ex: test_zipfile64): really too slow to be enabled
+#   "by default"
+# - tzdata: while needed to validate fully test_datetime, it makes
+#   test_datetime too slow (15-20 min on some buildbots) and so is disabled by
+#   default (see bpo-30822).
+RESOURCE_NAMES = ALL_RESOURCES + ('extralargefile', 'tzdata')
 
 class _ArgParser(argparse.ArgumentParser):
 
@@ -344,7 +353,7 @@ def _parse_args(args, **kwargs):
         for a in ns.use:
             for r in a:
                 if r == 'all':
-                    ns.use_resources[:] = RESOURCE_NAMES
+                    ns.use_resources[:] = ALL_RESOURCES
                     continue
                 if r == 'none':
                     del ns.use_resources[:]

Lib/test/test_regrtest.py

@@ -191,15 +191,26 @@ class ParseArgsTestCase(unittest.TestCase):
             with self.subTest(opt=opt):
                 ns = libregrtest._parse_args([opt, 'gui,network'])
                 self.assertEqual(ns.use_resources, ['gui', 'network'])
+
                 ns = libregrtest._parse_args([opt, 'gui,none,network'])
                 self.assertEqual(ns.use_resources, ['network'])
-                expected = list(libregrtest.RESOURCE_NAMES)
+
+                expected = list(libregrtest.ALL_RESOURCES)
                 expected.remove('gui')
                 ns = libregrtest._parse_args([opt, 'all,-gui'])
                 self.assertEqual(ns.use_resources, expected)
                 self.checkError([opt], 'expected one argument')
                 self.checkError([opt, 'foo'], 'invalid resource')
 
+                # all + a resource not part of "all"
+                ns = libregrtest._parse_args([opt, 'all,tzdata'])
+                self.assertEqual(ns.use_resources,
+                                 list(libregrtest.ALL_RESOURCES) + ['tzdata'])
+
+                # test another resource which is not part of "all"
+                ns = libregrtest._parse_args([opt, 'extralargefile'])
+                self.assertEqual(ns.use_resources, ['extralargefile'])
+
     def test_memlimit(self):
         for opt in '-M', '--memlimit':
             with self.subTest(opt=opt):

Misc/NEWS.d/next/Tests/2017-07-20-14-29-54.bpo-30822.X0wREo.rst

@@ -0,0 +1,5 @@
+regrtest: Exclude tzdata from regrtest --all. When running the test suite
+using --use=all / -u all, exclude tzdata since it makes test_datetime too
+slow (15-20 min on some buildbots) which then times out on some buildbots.
+Fix also regrtest command line parser to allow passing -u extralargefile to
+run test_zipfile64.