This allows to see the output of failing tests which might help finding the issue

While being at it: I'd like to provide an easy/easier way to run tests when building with CMake. It really bothers me that we don't test by default with configuremake based ECs (including meson, cmake, ...)

When using CMake the default setting to use is -DBUILD_TESTING=ON, although many projects already set it as default, which enables building the tests. Then you can do make test for makefile generators. Or more generically ctest --build-config <cfg>
So I'm thinking if there should be an option which enables the flag and the test or if a set runtest should automatically add the flag. I think using the ctest command would required adding build_type to iteratable options but that would be a good idea anyway