bpo-37552: Skip failing tests in strptime/strftime with UCRT version 17763.615 (#14460)

A bug in MSVC UCRT version 17763.615 (which has been fixed in newer versions) is causing test failures in some strptime/strftime tests when the default code page is c65001. This change selectively skips the tests affected by this.

1 files changed, 23 insertions, 1 deletions

diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index 423bb3e..4bf42e0 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -14,6 +14,7 @@ import gc
 import glob
 import importlib
 import importlib.util
+import locale
 import logging.handlers
 import nntplib
 import os
@@ -92,7 +93,7 @@ __all__ = [
     "bigmemtest", "bigaddrspacetest", "cpython_only", "get_attribute",
     "requires_IEEE_754", "skip_unless_xattr", "requires_zlib",
     "anticipate_failure", "load_package_tests", "detect_api_mismatch",
-    "check__all__", "skip_unless_bind_unix_socket",
+    "check__all__", "skip_unless_bind_unix_socket", "skip_if_buggy_ucrt_strfptime",
     "ignore_warnings",
     # sys
     "is_jython", "is_android", "check_impl_detail", "unix_shell",
@@ -2501,6 +2502,27 @@ def skip_unless_symlink(test):
     msg = "Requires functional symlink implementation"
     return test if ok else unittest.skip(msg)(test)
 
+_buggy_ucrt = None
+def skip_if_buggy_ucrt_strfptime(test):
+    """
+    Skip decorator for tests that use buggy strptime/strftime
+
+    If the UCRT bugs are present time.localtime().tm_zone will be
+    an empty string, otherwise we assume the UCRT bugs are fixed
+
+    See bpo-37552 [Windows] strptime/strftime return invalid
+    results with UCRT version 17763.615
+    """
+    global _buggy_ucrt
+    if _buggy_ucrt is None:
+        if(sys.platform == 'win32' and
+                locale.getdefaultlocale()[1]  == 'cp65001' and
+                time.localtime().tm_zone == ''):
+            _buggy_ucrt = True
+        else:
+            _buggy_ucrt = False
+    return unittest.skip("buggy MSVC UCRT strptime/strftime")(test) if _buggy_ucrt else test
+
 class PythonSymlink:
     """Creates a symlink for the current Python executable"""
     def __init__(self, link=None):