UNIT_TESTING_18501_SEARCH_USER

 - [x] Controller
    - [x] create function test_search_user_ok
    - [x] create function test_search_user_not_ok
    - [x] create function test_search_user_empty - The keyword search is empty
 - [x] Model
   - [x] create function test_search_user_ok
   - [x] create function test_search_user_notok
Update function name according to above comment.