Description:

Running the trial binary on any set of tests throws an exception that it cannot open a system file for writing. It seems like something should have been updated during the installation.

It seems like Debian hit the same problem a while back (http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=500942) but apparently it's fixed now due to the new release. Their fix seemed to be updating the plugins cache after install.

Steps to reproduce:

$ touch __init__.py
$ trial .
Traceback (most recent call last):
File "/usr/lib/python2.6/site-packages/twisted/python/usage.py", line 241, in parseOptions
self.postOptions()
File "/usr/lib/python2.6/site-packages/twisted/scripts/trial.py", line 295, in postOptions
self['reporter'] = self._loadReporterByName(self['reporter'])
File "/usr/lib/python2.6/site-packages/twisted/scripts/trial.py", line 281, in _loadReporterByName
for p in plugin.getPlugins(itrial.IReporter):
File "/usr/lib/python2.6/site-packages/twisted/plugin.py", line 200, in getPlugins
allDropins = getCache(package)
--- <exception caught here> ---
File "/usr/lib/python2.6/site-packages/twisted/plugin.py", line 179, in getCache
dropinPath.setContent(pickle.dumps(dropinDotCache))
File "/usr/lib/python2.6/site-packages/twisted/python/filepath.py", line 644, in setContent
f = sib.open('w')
File "/usr/lib/python2.6/site-packages/twisted/python/filepath.py", line 454, in open
return open(self.path, mode+'b')
exceptions.IOError: [Errno 13] Permission denied: '/usr/lib/python2.6/site-packages/twisted/plugins/dropin.cache.new'