bpo-33671: Add support.MS_WINDOWS and support.MACOS (GH-7800)

* Add support.MS_WINDOWS: True if Python is running on Microsoft Windows.
* Add support.MACOS: True if Python is running on Apple macOS.
* Replace support.is_android with support.ANDROID
* Replace support.is_jython with support.JYTHON
* Cleanup code to initialize unix_shell

Author: vstinner

Lib/test/_test_multiprocessing.py

@@ -103,8 +103,6 @@ def join_process(process):
 HAVE_GETVALUE = not getattr(_multiprocessing,
                             'HAVE_BROKEN_SEM_GETVALUE', False)
 
-WIN32 = (sys.platform == "win32")
-
 from multiprocessing.connection import wait
 
 def wait_for_handle(handle, timeout):
@@ -3806,7 +3804,7 @@ def record(*args):
 
 class TestInvalidHandle(unittest.TestCase):
 
-    @unittest.skipIf(WIN32, "skipped on Windows")
+    @unittest.skipIf(support.MS_WINDOWS, "skipped on Windows")
     def test_invalid_handles(self):
         conn = multiprocessing.connection.Connection(44977608)
         # check that poll() doesn't crash
@@ -4134,12 +4132,12 @@ def test_neg_timeout(self):
 
 class TestInvalidFamily(unittest.TestCase):
 
-    @unittest.skipIf(WIN32, "skipped on Windows")
+    @unittest.skipIf(support.MS_WINDOWS, "skipped on Windows")
     def test_invalid_family(self):
         with self.assertRaises(ValueError):
             multiprocessing.connection.Listener(r'\\.\test')
 
-    @unittest.skipUnless(WIN32, "skipped on non-Windows platforms")
+    @unittest.skipUnless(support.MS_WINDOWS, "skipped on non-Windows platforms")
     def test_invalid_family_win32(self):
         with self.assertRaises(ValueError):
             multiprocessing.connection.Listener('/var/test.pipe')
@@ -4265,7 +4263,7 @@ def test_lock(self):
 class TestCloseFds(unittest.TestCase):
 
     def get_high_socket_fd(self):
-        if WIN32:
+        if support.MS_WINDOWS:
             # The child process will not have any socket handles, so
             # calling socket.fromfd() should produce WSAENOTSOCK even
             # if there is a handle of the same number.
@@ -4283,7 +4281,7 @@ def get_high_socket_fd(self):
             return fd
 
     def close(self, fd):
-        if WIN32:
+        if support.MS_WINDOWS:
             socket.socket(socket.AF_INET, socket.SOCK_STREAM, fileno=fd).close()
         else:
             os.close(fd)

Lib/test/support/__init__.py

@@ -90,8 +90,8 @@
     "anticipate_failure", "load_package_tests", "detect_api_mismatch",
     "check__all__", "skip_unless_bind_unix_socket",
     # sys
-    "is_jython", "is_android", "check_impl_detail", "unix_shell",
-    "setswitchinterval",
+    "JYTHON", "ANDROID", "check_impl_detail", "unix_shell",
+    "setswitchinterval", "MS_WINDOWS", "MACOS",
     # network
     "HOST", "IPV6_ENABLED", "find_unused_port", "bind_port", "open_urlresource",
     "bind_unix_socket",
@@ -108,6 +108,21 @@
     "run_with_tz", "PGO", "missing_compiler_executable", "fd_count",
     ]
 
+
+# True if Python is running on Microsoft Windows.
+MS_WINDOWS = (sys.platform == 'win32')
+
+# True if Python is running on Apple macOS.
+MACOS = (sys.platform == 'darwin')
+
+# True if Python runs on Jython
+# (Python implemented in Java running in a Java VM)
+JYTHON = sys.platform.startswith('java')
+
+# True if Python runs on Android
+ANDROID = hasattr(sys, 'getandroidapilevel')
+
+
 class Error(Exception):
     """Base class for regression test exceptions."""
 
@@ -484,7 +499,7 @@ class USEROBJECTFLAGS(ctypes.Structure):
             raise ctypes.WinError()
         if not bool(uof.dwFlags & WSF_VISIBLE):
             reason = "gui not available (WSF_VISIBLE flag not set)"
-    elif sys.platform == 'darwin':
+    elif MACOS:
         # The Aqua Tk implementations on OS X can abort the process if
         # being called in an environment where a window server connection
         # cannot be made, for instance when invoked by a buildbot or ssh
@@ -600,7 +615,7 @@ def requires_mac_ver(*min_version):
     def decorator(func):
         @functools.wraps(func)
         def wrapper(*args, **kw):
-            if sys.platform == 'darwin':
+            if MACOS:
                 version_txt = platform.mac_ver()[0]
                 try:
                     version = tuple(map(int, version_txt.split('.')))
@@ -788,14 +803,12 @@ def dec(*args, **kwargs):
 
 requires_lzma = unittest.skipUnless(lzma, 'requires lzma')
 
-is_jython = sys.platform.startswith('java')
-
-is_android = hasattr(sys, 'getandroidapilevel')
-
-if sys.platform != 'win32':
-    unix_shell = '/system/bin/sh' if is_android else '/bin/sh'
-else:
+if MS_WINDOWS:
     unix_shell = None
+elif ANDROID:
+    unix_shell = '/system/bin/sh'
+else:
+    unix_shell = '/bin/sh'
 
 # Filename used for testing
 if os.name == 'java':
@@ -854,7 +867,7 @@ def dec(*args, **kwargs):
 
 # TESTFN_UNICODE is a non-ascii filename
 TESTFN_UNICODE = TESTFN + "-\xe0\xf2\u0258\u0141\u011f"
-if sys.platform == 'darwin':
+if MACOS:
     # In Mac OS X's VFS API file names are, by definition, canonically
     # decomposed Unicode, encoded using UTF-8. See QA1173:
     # http://developer.apple.com/mac/library/qa/qa2001/qa1173.html
@@ -866,7 +879,7 @@ def dec(*args, **kwargs):
 # encoded by the filesystem encoding (in strict mode). It can be None if we
 # cannot generate such filename.
 TESTFN_UNENCODABLE = None
-if os.name == 'nt':
+if MS_WINDOWS:
     # skip win32s (0) or Windows 9x/ME (1)
     if sys.getwindowsversion().platform >= 2:
         # Different kinds of characters from various languages to minimize the
@@ -881,8 +894,8 @@ def dec(*args, **kwargs):
                   'Unicode filename tests may not be effective'
                   % (TESTFN_UNENCODABLE, TESTFN_ENCODING))
             TESTFN_UNENCODABLE = None
-# Mac OS X denies unencodable filenames (invalid utf-8)
-elif sys.platform != 'darwin':
+# macOS denies unencodable filenames (invalid utf-8)
+elif not MACOS:
     try:
         # ascii and utf-8 cannot encode the byte 0xff
         b'\xff'.decode(TESTFN_ENCODING)
@@ -1523,7 +1536,7 @@ def gc_collect():
     objects to disappear.
     """
     gc.collect()
-    if is_jython:
+    if JYTHON:
         time.sleep(0.1)
     gc.collect()
     gc.collect()
@@ -1982,7 +1995,7 @@ def _check_docstrings():
     """Just used to check if docstrings are enabled"""
 
 MISSING_C_DOCSTRINGS = (check_impl_detail() and
-                        sys.platform != 'win32' and
+                        not MS_WINDOWS and
                         not sysconfig.get_config_var('WITH_DOC_STRINGS'))
 
 HAVE_DOCSTRINGS = (_check_docstrings.__doc__ is not None and
@@ -2592,7 +2605,7 @@ def __enter__(self):
                 except (ValueError, OSError):
                     pass
 
-            if sys.platform == 'darwin':
+            if MACOS:
                 # Check if the 'Crash Reporter' on OSX was configured
                 # in 'Developer' mode and warn that it will get triggered
                 # when it is.
@@ -2736,7 +2749,7 @@ def setswitchinterval(interval):
     # Setting a very low gil interval on the Android emulator causes python
     # to hang (issue #26939).
     minimum_interval = 1e-5
-    if is_android and interval < minimum_interval:
+    if ANDROID and interval < minimum_interval:
         global _is_android_emulator
         if _is_android_emulator is None:
             _is_android_emulator = (subprocess.check_output(
@@ -2782,7 +2795,7 @@ def fd_count():
             pass
 
     old_modes = None
-    if sys.platform == 'win32':
+    if MS_WINDOWS:
         # bpo-25306, bpo-31009: Call CrtSetReportMode() to not kill the process
         # on invalid file descriptor if Python is compiled in debug mode
         try:

Lib/test/test_c_locale_coercion.py

@@ -27,7 +27,7 @@
 
 # Apply some platform dependent overrides
 if sys.platform.startswith("linux"):
-    if test.support.is_android:
+    if test.support.ANDROID:
         # Android defaults to using UTF-8 for all system interfaces
         EXPECTED_C_LOCALE_STREAM_ENCODING = "utf-8"
         EXPECTED_C_LOCALE_FS_ENCODING = "utf-8"
@@ -335,7 +335,7 @@ def _check_c_locale_coercion(self,
             # locale environment variables are undefined or empty. When
             # this code path is run with environ['LC_ALL'] == 'C', then
             # LEGACY_LOCALE_WARNING is printed.
-            if (test.support.is_android and
+            if (test.support.ANDROID and
                     _expected_warnings == [CLI_COERCION_WARNING]):
                 _expected_warnings = None
             self._check_child_encoding_details(base_var_dict,

Lib/test/test_cmd_line.py

@@ -187,8 +187,8 @@ def test_undecodable_code(self):
         if not stdout.startswith(pattern):
             raise AssertionError("%a doesn't start with %a" % (stdout, pattern))
 
-    @unittest.skipUnless((sys.platform == 'darwin' or
-                support.is_android), 'test specific to Mac OS X and Android')
+    @unittest.skipUnless((support.MACOS or support.ANDROID),
+                         'test specific to macOS and Android')
     def test_osx_android_utf8(self):
         def check_output(text):
             decoded = text.decode('utf-8', 'surrogateescape')

Lib/test/test_codeop.py

@@ -3,12 +3,12 @@
    Nick Mathewson
 """
 import unittest
-from test.support import is_jython
+from test import support
 
 from codeop import compile_command, PyCF_DONT_IMPLY_DEDENT
 import io
 
-if is_jython:
+if support.JYTHON:
     import sys
 
     def unify_callables(d):
@@ -21,7 +21,7 @@ class CodeopTests(unittest.TestCase):
 
     def assertValid(self, str, symbol='single'):
         '''succeed iff str is a valid piece of code'''
-        if is_jython:
+        if support.JYTHON:
             code = compile_command(str, "<input>", symbol)
             self.assertTrue(code)
             if symbol == "single":
@@ -60,7 +60,7 @@ def test_valid(self):
         av = self.assertValid
 
         # special case
-        if not is_jython:
+        if not support.JYTHON:
             self.assertEqual(compile_command(""),
                              compile("pass", "<input>", 'single',
                                      PyCF_DONT_IMPLY_DEDENT))

Lib/test/test_faulthandler.py

@@ -6,7 +6,7 @@
 import subprocess
 import sys
 from test import support
-from test.support import script_helper, is_android
+from test.support import script_helper
 import tempfile
 import threading
 import unittest
@@ -18,7 +18,6 @@
     _testcapi = None
 
 TIMEOUT = 0.5
-MS_WINDOWS = (os.name == 'nt')
 
 def expected_traceback(lineno1, lineno2, header, min_count=1):
     regex = header
@@ -31,7 +30,7 @@ def expected_traceback(lineno1, lineno2, header, min_count=1):
 
 def skip_segfault_on_android(test):
     # Issue #32138: Raising SIGSEGV on Android may not cause a crash.
-    return unittest.skipIf(is_android,
+    return unittest.skipIf(support.ANDROID,
                            'raising SIGSEGV on Android is unreliable')(test)
 
 @contextmanager
@@ -121,7 +120,7 @@ def check_windows_exception(self, code, line_number, name_regex, **kw):
     @unittest.skipIf(sys.platform.startswith('aix'),
                      "the first page of memory is a mapped read-only on AIX")
     def test_read_null(self):
-        if not MS_WINDOWS:
+        if not support.MS_WINDOWS:
             self.check_fatal_error("""
                 import faulthandler
                 faulthandler.enable()
@@ -732,7 +731,7 @@ def test_stderr_None(self):
             with self.check_stderr_none():
                 faulthandler.register(signal.SIGUSR1)
 
-    @unittest.skipUnless(MS_WINDOWS, 'specific to Windows')
+    @unittest.skipUnless(support.MS_WINDOWS, 'specific to Windows')
     def test_raise_exception(self):
         for exc, name in (
             ('EXCEPTION_ACCESS_VIOLATION', 'access violation'),
@@ -747,7 +746,7 @@ def test_raise_exception(self):
                 3,
                 name)
 
-    @unittest.skipUnless(MS_WINDOWS, 'specific to Windows')
+    @unittest.skipUnless(support.MS_WINDOWS, 'specific to Windows')
     def test_ignore_exception(self):
         for exc_code in (
             0xE06D7363,   # MSC exception ("Emsc")
@@ -763,7 +762,7 @@ def test_ignore_exception(self):
             self.assertEqual(output, [])
             self.assertEqual(exitcode, exc_code)
 
-    @unittest.skipUnless(MS_WINDOWS, 'specific to Windows')
+    @unittest.skipUnless(support.MS_WINDOWS, 'specific to Windows')
     def test_raise_nonfatal_exception(self):
         # These exceptions are not strictly errors. Letting
         # faulthandler display the traceback when they are
@@ -791,7 +790,7 @@ def test_raise_nonfatal_exception(self):
             self.assertIn(exitcode,
                           (exc, exc & ~0x10000000))
 
-    @unittest.skipUnless(MS_WINDOWS, 'specific to Windows')
+    @unittest.skipUnless(support.MS_WINDOWS, 'specific to Windows')
     def test_disable_windows_exc_handler(self):
         code = dedent("""
             import faulthandler

Lib/test/test_import/__init__.py

@@ -20,7 +20,7 @@
 
 import test.support
 from test.support import (
-    EnvironmentVarGuard, TESTFN, check_warnings, forget, is_jython,
+    EnvironmentVarGuard, TESTFN, check_warnings, forget, JYTHON,
     make_legacy_pyc, rmtree, run_unittest, swap_attr, swap_item, temp_umask,
     unlink, unload, create_empty_file, cpython_only, TESTFN_UNENCODABLE,
     temp_dir, DirsOnSysPath)
@@ -148,7 +148,7 @@ def test_import(self):
         def test_with_extension(ext):
             # The extension is normally ".py", perhaps ".pyw".
             source = TESTFN + ext
-            if is_jython:
+            if JYTHON:
                 pyc = TESTFN + "$py.class"
             else:
                 pyc = TESTFN + ".pyc"

Lib/test/test_io.py

@@ -583,7 +583,7 @@ def test_large_file_ops(self):
         # On Windows and Mac OSX this test consumes large resources; It takes
         # a long time to build the >2 GiB file and takes >2 GiB of disk space
         # therefore the resource must be enabled to run this test.
-        if sys.platform[:3] == 'win' or sys.platform == 'darwin':
+        if support.MS_WINDOWS or support.MACOS:
             support.requires(
                 'largefile',
                 'test requires %s bytes and a long time to run' % self.LARGE)

Lib/test/test_largefile.py

@@ -5,6 +5,7 @@
 import stat
 import sys
 import unittest
+from test import support
 from test.support import TESTFN, requires, unlink
 import io  # C implementation of io
 import _pyio as pyio # Python implementation of io
@@ -145,7 +146,7 @@ def setUpModule():
     # takes a long time to build the >2 GiB file and takes >2 GiB of disk
     # space therefore the resource must be enabled to run this test.
     # If not, nothing after this line stanza will be executed.
-    if sys.platform[:3] == 'win' or sys.platform == 'darwin':
+    if support.MS_WINDOWS or support.MACOS:
         requires('largefile',
                  'test requires %s bytes and a long time to run' % str(size))
     else: