'Make sure that checkpoint errors are thrown appropriately.'

def test_checkpoint_conflict(self):

    config3 = os.path.join(self.dir1, 'config3.txt')
    self.reverter.register_file_creation(True, config3)
    update_file(config3, 'This    is    a    new    file!')
    self.reverter.add_to_checkpoint(self.sets[2], 'save1')
    self.reverter.add_to_temp_checkpoint(self.sets[0], 'save2')
    self.assertRaises(errors.ReverterError, self.reverter.add_to_checkpoint, self.sets[2], 'save3')
    self.reverter.add_to_checkpoint(self.sets[1], 'save4')
    self.assertRaises(errors.ReverterError, self.reverter.add_to_checkpoint, set([config3]), 'invalid    save')
