commit 850c6e27a12858ad3e4de1a019df496d822f1dd6
Author: Gregory M. Turner <gmt@be-evil.net>
Date:   Wed Dec 3 04:50:19 2014 -0800

    Lib/test/test_metaclass.py: virtual sub-metas
    
    Test capturing that type machinery ignores __subclasscheck__ and
    __instancecheck__ when determining the effective metaclass.
    
    Signed-off-by: Gregory M. Turner <gmt@be-evil.net>

diff --git a/Lib/test/test_metaclass.py b/Lib/test/test_metaclass.py
index e6fe20a..e0f0eac 100644
--- a/Lib/test/test_metaclass.py
+++ b/Lib/test/test_metaclass.py
@@ -246,6 +246,39 @@ Test failures in looking up the __prepare__ method work.
     [...]
     test.test_metaclass.ObscureException
 
+Virtual types ought not to affect metaclass selection.
+
+    >>> class VMA(type): pass
+    >>> class MMA(type):
+    ...     def __subclasscheck__(m, C):
+    ...         return (issubclass(C, VMA) or m is C
+    ...             ) if m is MA else super().__subclasscheck__(C)
+    ...     def __instancecheck__(m, i):
+    ...         return (isinstance(i, VMA) or m is type(i)
+    ...             ) if m is MA else super().__instancecheck__(i)
+    >>> class MA(type, metaclass=MMA): pass
+    >>> class SMA(MA): pass
+    >>> class A(metaclass=MA): pass
+    >>> try:
+    ...     class B(A, metaclass=VMA): pass
+    ... except TypeError:
+    ...     print('TypeError (tl;dr)')
+    TypeError (tl;dr)
+    >>> issubclass(VMA, MA)
+    True
+    >>> class C(type, metaclass=SMA): pass
+    >>> class D(A, C): pass
+    >>> type(D)
+    <class 'test.test_metaclass.SMA'>
+    >>> type(A)
+    <class 'test.test_metaclass.MA'>
+    >>> type(C)
+    <class 'test.test_metaclass.SMA'>
+    >>> issubclass(SMA, MA)
+    False
+    >>> issubclass(MA, SMA)
+    False
+
 """
 
 import sys