only do CUDA-specific test when CUDA is enabled

Signed-off-by: Carl Pearson <cwpears@sandia.gov>

unit_tests/CMakeLists.txt

@@ -76,23 +76,24 @@ if(KOKKOSCOMM_ENABLE_MPI)
       ${MPIEXEC_EXECUTABLE} ${MPIEXEC_NUMPROC_FLAG} 2 ./test-mpi
   )
 
-  add_executable(test-mpi-sendrecv)
-  target_sources(test-mpi-sendrecv PRIVATE mpi/test_mpi_sendrecv.cpp)
-  target_link_libraries(test-mpi-sendrecv MPI::MPI_CXX)
+  if (KOKKOS_ENABLE_CUDA)
+    add_executable(test-mpi-cuda-sendrecv)
+    target_sources(test-mpi-cuda-sendrecv PRIVATE mpi/test_mpi_cuda_sendrecv.cpp)
+    target_link_libraries(test-mpi-cuda-sendrecv MPI::MPI_CXX)
 
-  # MPICH needs dynamic cudart (we think, pmodels/mpich#7304)
-  if (KOKKOSCOMM_IMPL_MPI_IS_MPICH AND KOKKOS_ENABLE_CUDA)
-    # this one doesn't work for reasons I don't understand
-    # set_target_properties(test-mpi-sendrecv PROPERTIES CUDA_RUNTIME_LIBRARY Shared)
-    # this one does work
-    target_compile_options(test-mpi-sendrecv PUBLIC --cudart shared)
-    target_link_options(test-mpi-sendrecv PUBLIC --cudart shared)
+    # MPICH needs dynamic cudart (we think, pmodels/mpich#7304)
+    if (KOKKOSCOMM_IMPL_MPI_IS_MPICH AND KOKKOS_ENABLE_CUDA)
+      # Setting the CUDA_RUNTIME_LIBRARY property on this target to "Shared" doesn't work for
+      # reasons I don't understand.
+      target_compile_options(test-mpi-cuda-sendrecv PUBLIC --cudart shared)
+      target_link_options(test-mpi-cuda-sendrecv PUBLIC --cudart shared)
+    endif()
+    add_test(
+      NAME test-mpi-cuda-sendrecv
+      COMMAND
+          ${MPIEXEC_EXECUTABLE} ${MPIEXEC_NUMPROC_FLAG} 2 ./test-mpi-cuda-sendrecv
+    )
   endif()
-  add_test(
-    NAME test-mpi-sendrecv
-    COMMAND
-        ${MPIEXEC_EXECUTABLE} ${MPIEXEC_NUMPROC_FLAG} 2 ./test-mpi-sendrecv
-)
 
 
 endif()