Use CTEST_PARALLEL_LEVEL instead of --parallel

Author: bdutro

tests/CMakeLists.txt

@@ -9,7 +9,7 @@ ProcessorCount(NUM_CORES)
 
 if (NOT NUM_CORES EQUAL 0)
   set(CTEST_BUILD_FLAGS -j${NUM_CORES})
-  set(ctest_test_args "--parallel ${NUM_CORES}")
+  set(CTEST_PARALLEL_LEVEL ${NUM_CORES})
 endif()
 
 message(STATUS "Found " ${NUM_CORES} " cores in machine (for ctest)")
@@ -21,4 +21,4 @@ add_dependencies(regress stf stf_writer_test)
 
 add_custom_command(TARGET regress POST_BUILD
                    COMMAND ${CMAKE_COMMAND} -E echo "Running tests..."
-                   COMMAND ${CMAKE_CTEST_COMMAND} ${ctest_test_args})
+                   COMMAND ${CMAKE_CTEST_COMMAND})