Clone test of ZODB.persistentclass.PersistentMetaClass to its own file.

Preparation for kliling the last ZODB-dependent test in the standalone
'persistent' package.

src/ZODB/tests/test_persistentclass.py

+##############################################################################
+#
+# Copyright (c) 2003 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+
+from doctest import DocTestSuite 
+import unittest
+
+
+def test_new_ghost_w_persistent_class():
+    """
+    Peristent meta classes work with PickleCache.new_ghost:
+
+    >>> import ZODB.persistentclass
+
+    >>> class PC:
+    ...     __metaclass__ = ZODB.persistentclass.PersistentMetaClass
+
+    >>> PC._p_oid
+    >>> PC._p_jar
+    >>> PC._p_serial
+    >>> PC._p_changed
+    False
+
+    >>> import persistent
+    >>> jar = object()
+    >>> cache = persistent.PickleCache(jar, 10, 100)
+    >>> cache.new_ghost('1', PC)
+
+    >>> PC._p_oid
+    '1'
+    >>> PC._p_jar is jar
+    True
+    >>> PC._p_serial
+    >>> PC._p_changed
+    False
+    """
+
+
+def test_suite():
+    return unittest.TestSuite((
+        DocTestSuite(),
+    ))