[3.7] bpo-41009: fix requires_OS_version() class decorator (GH-20942) (GH-20949)

Signed-off-by: Christian Heimes <christian@python.org>

Automerge-Triggered-By: @tiran.
(cherry picked from commit bb6ec14479f18c32e71e43f2785f177aa17aabbd)

Co-authored-by: Christian Heimes <christian@python.org>

2 files changed, 21 insertions, 19 deletions

diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index b198c2ca763..b78451b9e6c 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -560,25 +560,25 @@ def _requires_unix_version(sysname, min_version):
     For example, @_requires_unix_version('FreeBSD', (7, 2)) raises SkipTest if
     the FreeBSD version is less than 7.2.
     """
-    def decorator(func):
-        @functools.wraps(func)
-        def wrapper(*args, **kw):
-            if platform.system() == sysname:
-                version_txt = platform.release().split('-', 1)[0]
-                try:
-                    version = tuple(map(int, version_txt.split('.')))
-                except ValueError:
-                    pass
-                else:
-                    if version < min_version:
-                        min_version_txt = '.'.join(map(str, min_version))
-                        raise unittest.SkipTest(
-                            "%s version %s or higher required, not %s"
-                            % (sysname, min_version_txt, version_txt))
-            return func(*args, **kw)
-        wrapper.min_version = min_version
-        return wrapper
-    return decorator
+    import platform
+    min_version_txt = '.'.join(map(str, min_version))
+    version_txt = platform.release().split('-', 1)[0]
+    if platform.system() == sysname:
+        try:
+            version = tuple(map(int, version_txt.split('.')))
+        except ValueError:
+            skip = False
+        else:
+            skip = version < min_version
+    else:
+        skip = False
+
+    return unittest.skipIf(
+        skip,
+        f"{sysname} version {min_version_txt} or higher required, not "
+        f"{version_txt}"
+    )
+
 
 def requires_freebsd_version(*min_version):
     """Decorator raising SkipTest if the OS is FreeBSD and the FreeBSD version is
diff --git a/Misc/NEWS.d/next/Tests/2020-06-17-17-27-07.bpo-41009.Rvn6OQ.rst b/Misc/NEWS.d/next/Tests/2020-06-17-17-27-07.bpo-41009.Rvn6OQ.rst
new file mode 100644
index 00000000000..1208c119a35
--- /dev/null
+++ b/Misc/NEWS.d/next/Tests/2020-06-17-17-27-07.bpo-41009.Rvn6OQ.rst
@@ -0,0 +1,2 @@
+Fix use of ``support.require_{linux|mac|freebsd}_version()`` decorators as
+class decorator.