here is the patch for 2.7.

Dave: I don't know if or when the patch will be accepted, as this is a new 
feature. In the meantime, you can easily patch your system. As the code changes 
are all in Python, you don't need to recompile. Going to your standard library 
directory and running a command like the following should do the trick:

filterdiff -i '*/doctest.py' issue12055-27.diff | patch