Log information about the objects replaced by Python Mock, patch. Combine with similar logging in your application to debug patching.

mock.py.diff

--- mock.py~	2013-07-31 13:20:48.000000000 -0400
+++ mock.py	2013-07-31 17:43:13.000000000 -0400
@@ -32,9 +32,12 @@
 __version__ = '0.8.0'
 
 
+import logging
 import pprint
 import sys
 
+logger = logging.getLogger(__name__)
+
 try:
     import inspect
 except ImportError:
@@ -1112,7 +1115,8 @@
     try:
         return getattr(thing, comp)
     except AttributeError:
-        __import__(import_path)
+        imported_thing = __import__(import_path)
+        logger.debug('imported_thing: %r', imported_thing)
         return getattr(thing, comp)
 
 
@@ -1120,10 +1124,12 @@
     components = target.split('.')
     import_path = components.pop(0)
     thing = __import__(import_path)
+    logger.debug('thing: %r', thing)
 
     for comp in components:
         import_path += ".%s" % comp
         thing = _dot_lookup(thing, comp, import_path)
+        logger.debug('thing: %r', thing)
     return thing
 
 
@@ -1272,6 +1278,7 @@
         new_callable = self.new_callable
         self.target = self.getter()
 
+        logger.debug('target: %r', self.target)
         original, local = self.get_original()
 
         if new is DEFAULT and autospec is False: