libkolabxml build dependencies

Were trying to build the libkolabxml and/or libkolab on a gentoo  
system. The KDE-maintainers added both libraries to the testing overlay.
libkolab pulls in around 100 different packages.
libkolabxml also needs QtTest i think, but this requirement is not  
written anywhere.
Is there a list of what is really needed to build libkolabxml without  
building the whole KDE toolchain?
Manual compilation leads to the same result:

[ 87%] Building CXX object  
tests/CMakeFiles/bindingstest.dir/bindingstest.cpp.o
In file included from /root/libkolabxml-0.6.0/tests/bindingstest.cpp:1:0:
/root/libkolabxml-0.6.0/tests/bindingstest.h:5:25: fatal error:  
QtTest/QtTest: No such file or directory
compilation terminated.

regards,
Alexander