'Test a simple usage of unstage_paths().'

def test_unstage_paths(self):

    self.commit_files()
    self.write_file(u'A', u'change')
    self.git(u'add', u'A')
    gitcmds.unstage_paths([u'A'])
    self.model.update_status()
    self.assertTrue((u'A' not in self.model.staged))
    self.assertTrue((u'A' in self.model.modified))
