test_portalsky error: Class 'idPortalSky' not found on 'info_portalsky_1'.

[hemebond]

The testmaps/test_portalsky map has the following error:

==== Processing events ====
SpawnPlayer: 0
     7 msec to load testmaps/test_portalsky
idRenderWorld::GenerateAllInteractions, msec = 0, staticAllocCount = 0.
interactionTable size: 88880 bytes
6 interaction take 912 bytes
----- Warnings -----
during testmaps/test_portalsky...
[RUN WARNS]: Could not spawn 'info_portalsky'.  Class 'idPortalSky' not found  on 'info_portalsky_1'.
[RUN WARNS]: Could not spawn 'info_portalsky'.  Class 'idPortalSky' not found  on 'info_portalsky_2'.
----- 2 warnings -----