Code review comment for lp://staging/~senan/ubuntu-autopilot-tests/DiskUsageAnalyser

You need something like this:

def setUp(self):
    '''Set-up method'''
    super(DiskUsageAnalyzerTests, self).setUp()
    #mock out the home dir
    self.home_dir = self._patch_home()
    ....

def _patch_home(self):
    #make a temp dir
    temp_dir = tempfile.mkdtemp()
    logger.debug("Created fake home directory " + temp_dir)
    self.addCleanup(shutil.rmtree, temp_dir)
    patcher = mock.patch.dict('os.environ', {'HOME': temp_dir})
    patcher.start()
    logger.debug("Patched home to fake home directory " + temp_dir)
    self.addCleanup(patcher.stop)
    return temp_dir