[MR,CT]{issue} I01, I02 - Login with wrong username. Login with empty data.
[MR,CT]{issue} I03, I04, I05, I06 - Login with new registered User. Register with existing username. Register with wrong confirm password. Register with empty data.
[MR,CT]{issue} I03, I04, I05, I06 - Login with new registered User. Register with existing username. Register with wrong confirm password. Register with empty data.