Oracle - ORA-00959: tablespace 'LONGSPACE' does not exist

I was cleaning up an Oracle 12c R2 database prior to reinstalling IBM MDM AE 11.5.0.5, and hit a small glitch with two of the tablespaces: -

drop tablespace LongSpace;

drop tablespace LongSpace
*
ERROR at line 1:
ORA-00959: tablespace 'LONGSPACE' does not exist

even though it really does exist: -

select tablespace_name, con_id from cdb_tablespaces;

TABLESPACE_NAME     CON_ID
------------------------------ ----------
SYSTEM 0
SYSAUX 0
UNDOTBS1 0
TEMP 0
USERS 0
IndexSpace 0
LongSpace 0

7 rows selected.

The solution, as ever, was simple: -

drop tablespace "IndexSpace";

Tablespace dropped.

drop tablespace "LongSpace";

Tablespace dropped.

That'll teach me to use mixed-case tablespace names !