I lost datafiles of rollback segment of Test DB and it is closed now => I can not drop the tablespace.

Database was not in archive log mode, but lossing of last changes is OK.

What is the best way to get database opened?

P.S.
So far I used 'CREATE CONTROLFILE' with entries for lost files removed, but got an error on 'ALTER DATABASE OPEN RESETLOGS':

SQL> ALTER DATABASE OPEN RESETLOGS;
ALTER DATABASE OPEN RESETLOGS
*
ERROR at line 1:
ORA-01194: file 1 needs more recovery to be consistent
ORA-01110: data file 1: 'G:\ORACLE\ORADATA\ORCC\SYSTEM01.DBF'