given that user logged into application,on homepage->my profile->change login info->username text box, requirements are
username must be between 2 and 50 characters.
Only letters, digits, ".", "-", and "_" are allowed.
whereas when we enter only 2 chars, it gives error message as "username must be at least 6 characters,
Again system accepting 3 and more chars but not the two chars
See the UserFormController for the preferred behavior and error message to display