def _test_output(ret, action, params):

    if action == 'list':
        ret['comment'] += 'The list action will just list an entity and will make no changes.\n'
    elif action == 'create' or action == 'add':
        ret['comment'] += 'The create action will attempt to create an entity if it does not already exist.\n'
    elif action == 'delete':
        ret['comment'] += 'The delete action will attempt to delete an existing entity if it exists.\n'
    elif action == 'manage':
        ret['comment'] += 'The manage action will create a new entity if it does not exist.  If it does exist, it will be enforced' \
                          'to the desired state.\n'
    elif action == 'modify':
        ret['comment'] += 'The modify action will attempt to modify an existing entity only if it exists.\n'

    ret['comment'] += 'An iControl REST Request will be made using the parameters:\n'
    ret['comment'] += json.dumps(params, indent=4)

    ret['changes'] = {}
    # Return ``None`` when running with ``test=true``.
    ret['result'] = None

    return ret
For testing just output what the state will attempt to do without actually doing it.
dataset/ETHPy150Open saltstack/salt/salt/states/bigip.py/_test_output