I think you're right that the method and line number are printed. The purpose of the doc reference is to print the test's documentation string on failure as well.

I don't think that the getframe approach cleans up the code any - to me it just looks like more code that I have to parse when I'm reading the test (or I'll get halfway through parsing it and realize that it's boilerplate, but I don't think that's much better). A cleaner answer may be to do something along the lines of:
def get_doc_string():
  sys.getframe(1).f_code.co_name # gets the name of the caller function
  return eval('self'+fn+'.__doc__')
and then call it as self.assertTrue(1=0, get_doc_string())

But overall I think it's probably more readable just to put a string constant in the assert statement.