[CMake] Weird ctest behaviour

[Johny]

Hey,

I have a ctest script which i am using as a test in my build like this

add_test ( ctest -S script.cmake)

however once the script finishes executing i get a CMake error saying my 
CTEST_SOURCE_DIRECTORY, CTEST_BINARY_DIRECTORY and CTEST_COMMAND are not 
set. I've tried all sort of things from running the script directly from 
the shell and also through ctest as a part of more tests but i still get 
the same error. The script does not call cmake at any point of time or 
do anything with the source and binary directories. Whats going wrong?

Cheers,
Johny