Can I test multiple generators with one build of cmake?

That’s exactly my point! The only way I know how to test the Xcode generator is by building cmake with Xcode, which is s-l-o-o-o-w:

cmake -DBUILD_TESTING=1 -S . -B build-xcode -G 'Xcode'
cmake --build build-xcode --config Release
ctest -C Release --test-dir build-xcode --parallel

The generator used for testing is automatically chosen to be the generator used for building. Is there a way to override that? I don’t know of one.

Should I know that? Is there a document somewhere that talks about how to test CMake? I’m having other struggles a document like that could answer, like not knowing how to set up an appropriate environment.