Testing our CMake Modules

We created multiple additional functions for CMake. They became quite a lot, and we need to (unit) test them.

There are simple ones, that are only variable bases like:

function(join_list LIST GLUE)

These can be tested with a custom CMake Script, that checks the results. For this we also wrote a set of assert-macros.

This becomes way harder when the functions are target based:

function(target_my_custom_property_set TARGET VALUE)

We need a multiple CMakeLists.txt Files that need to be configured. Configuration must succeed or fail with specified messages. Also the result files must be checked.

I wonder, is there a easier way? Is there a existing framework? How does Kitware test the shipped modules?