`BUILD_TESTS` does not actually build tests

[thyssentishman]

After successfully compiling flann on OpenBSD, I'm trying to run tests by running make test. This however doesn't work as the test binaries can not be found despite building with the BUILD_TESTS switch set to ON:

cmake \
-DBUILD_C_BINDINGS=ON \
-DBUILD_PYTHON_BINDINGS=OFF \
-DBUILD_MATLAB_BINDINGS=OFF \
-DBUILD_CUDA_LIB=OFF \
-DBUILD_EXAMPLES=OFF \
-DBUILD_TESTS=ON \
-DBUILD_DOC=OFF \
-DUSE_OPENMP=OFF \
-DUSE_MPI=OFF .. && make

Instead I first have to run make tests to compile them and then run them with make test. Is this intended? If yes, what is the purpose of the BUILD_TESTS switch then?