Make ZODB-/transaction-dependent functests conditional on their importability.

persistent/tests/test_PickleCache.py

@@ -90,10 +90,22 @@ Caches have a new_ghost method that:
 
     <<< cache.total_estimated_size # WTF?
     0
+    """
 
+try:
+    import transaction
+    import ZODB
+except ImportError:
+    pass
+else:
+    def new_ghost_w_persistent_classes():
+        """
+        Peristent meta classes work too:
 
-Peristent meta classes work too:
-
+            >>> import persistent
+            >>> from persistent.tests.utils import ResettingJar
+            >>> jar = ResettingJar()
+            >>> cache = persistent.PickleCache(jar, 10, 100)
             >>> import ZODB.persistentclass
             >>> class PC:
             ...     __metaclass__ = ZODB.persistentclass.PersistentMetaClass
@@ -112,10 +124,8 @@ Peristent meta classes work too:
             >>> PC._p_serial
             >>> PC._p_changed
             False
-
         """
 
-if 0: # this test doesn't belong here!
     def cache_invalidate_and_minimize_used_to_leak_None_ref():
         """Persistent weak references
 

persistent/tests/test_wref.py

@@ -19,6 +19,12 @@ else:
     from doctest import DocTestSuite
 
 def test_suite():
+    try:
+        import transaction
+        import ZODB
+    except ImportError:
+        return unittest.TestSuite()
+    else:
         return DocTestSuite('persistent.wref')
 
 if __name__ == '__main__':