[1.2.x] Fixed #14454 -- converted admin_widgets tests from doctests to unittests. We have always been at war with doctests. Thanks to prestontimmons for the patch. Backport of [14221].

      git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14222 bcc190cf-cafb-0310-a4f2-bffc1f526a37