Perhaps something else is wrong with my setup. I didn't have trouble running the unit tests pre-1.0. I've followed the dev setup instructions exactly and no matter what I do, I cannot get the unit tests to work (regardless of this change). Some of them pass, but most cannot import diffviewer:

======================================================================
ERROR: Failure: AttributeError ('module' object has no attribute 'diffviewer')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/pymodules/python2.5/nose/loader.py", line 379, in loadTestsFromName
    addr.filename, addr.module)
  File "/usr/lib/pymodules/python2.5/nose/importer.py", line 39, in importFromPath
    return self.importFromDir(dir_path, fqname)
  File "/usr/lib/pymodules/python2.5/nose/importer.py", line 86, in importFromDir
    mod = load_module(part_fqname, fh, filename, desc)
  File "/home/pil/reviewboard-dev/reviewboard/reviewboard/webapi/tests.py", line 10, in <module>
    import reviewboard.webapi.json as webapi
  File "/home/pil/reviewboard-dev/reviewboard/reviewboard/webapi/json.py", line 32, in <module>
    from reviewboard.diffviewer.forms import UploadDiffForm, EmptyDiffError
  File "/home/pil/reviewboard-dev/reviewboard/reviewboard/diffviewer/forms.py", line 7, in <module>
    from reviewboard.diffviewer.diffutils import DEFAULT_DIFF_COMPAT_VERSION
  File "/home/pil/reviewboard-dev/reviewboard/reviewboard/diffviewer/diffutils.py", line 30, in <module>
    from reviewboard.scmtools.core import PRE_CREATION, HEAD
  File "/home/pil/reviewboard-dev/reviewboard/reviewboard/scmtools/core.py", line 1, in <module>
    import reviewboard.diffviewer.parser as diffparser
AttributeError: 'module' object has no attribute 'diffviewer'

----------------------------------------------------------------------

It's in my python and a python process can import reviewboard.diffviewer.parser just fine... I can't find a way to drop into the debugger with manage.py test like you can with nosetests, so I have no idea why it won't work. Everything else seems to work fine...

Can you load the test fixtures including test_scmtools with the error I get?