Test Suite ERROR: bzrlib.plugins.builddeb.tests.test_upstream.TarfileSourceTests.test_fetch_tarball_repackest_fetch_tarball_repack

Environment: Trunk r507 on natty amd64, with distro-packaged bzr.

ERROR: bzrlib.plugins.builddeb.tests.test_upstream.TarfileSourceTests.test_fetch_tarball_repack
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_StringException: Text attachment: log
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105.564 opening working tree '/tmp/testbzr-cPItrB.tmp'
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Text attachment: traceback
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Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/testtools/runtest.py", line 169, in _run_user
    return fn(*args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/testtools/testcase.py", line 499, in _run_test_method
    return self._get_test_method()()
  File "/home/stefanor/.bazaar/plugins/builddeb/tests/test_upstream.py", line 361, in test_fetch_tarball_repack
    source.fetch_tarball("foo", "2.0", "bar"))
  File "/home/stefanor/.bazaar/plugins/builddeb/upstream.py", line 526, in fetch_tarball
    repack_tarball(self.path, dest_name, target_dir=target_dir)
  File "/home/stefanor/.bazaar/plugins/builddeb/repack_tarball.py", line 243, in repack_tarball
    force_gz=force_gz)
  File "/home/stefanor/.bazaar/plugins/builddeb/repack_tarball.py", line 190, in _repack_other
    repacker.repack(target_f)
  File "/home/stefanor/.bazaar/plugins/builddeb/repack_tarball.py", line 115, in repack
    zip = zipfile.ZipFile(self.source_f, "r")
  File "/usr/lib/python2.6/zipfile.py", line 696, in __init__
    self._GetContents()
  File "/usr/lib/python2.6/zipfile.py", line 716, in _GetContents
    self._RealGetContents()
  File "/usr/lib/python2.6/zipfile.py", line 728, in _RealGetContents
    raise BadZipfile, "File is not a zip file"
BadZipfile: File is not a zip file
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