鼻子测试覆盖率许可错误

nosetests --with-coverage --cover-html --cover-html-dir=/tmp/cache

Traceback (most recent call last):
  File "/usr/bin/nosetests", line 8, in <module>
    load_entry_point('nose==0.11.1', 'console_scripts', 'nosetests')()
  File "/usr/lib/pymodules/python2.6/nose/core.py", line 113, in __init__
    argv=argv, testRunner=testRunner, testLoader=testLoader)
  File "/usr/lib/python2.6/unittest.py", line 817, in __init__
    self.runTests()
  File "/usr/lib/pymodules/python2.6/nose/core.py", line 192, in runTests
    result = self.testRunner.run(self.test)
  File "/usr/lib/pymodules/python2.6/nose/core.py", line 63, in run
    result.printErrors()
  File "/usr/lib/pymodules/python2.6/nose/result.py", line 88, in printErrors
    self.config.plugins.report(self.stream)
  File "/usr/lib/pymodules/python2.6/nose/plugins/manager.py", line 82, in __call__
    return self.call(*arg, **kw)
  File "/usr/lib/pymodules/python2.6/nose/plugins/manager.py", line 150, in simple
    result = meth(*arg, **kw)
  File "/usr/lib/pymodules/python2.6/nose/plugins/cover.py", line 168, in report
    coverage.annotate(files.values())
  File "/usr/lib/python2.6/dist-packages/coverage.py", line 995, in annotate
    return the_coverage.annotate(*args, **kw)
  File "/usr/lib/python2.6/dist-packages/coverage.py", line 906, in annotate
    self.annotate_file(filename, statements, excluded, missing, directory)
  File "/usr/lib/python2.6/dist-packages/coverage.py", line 921, in annotate_file
    dest = open(dest_file, 'w')
IOError: [Errno 13] Permission denied: '/usr/lib/python2.6/email/iterators.py,cover'