diff --git a/CMakeLists.txt b/CMakeLists.txt
index 974b2c325a..4c041d5699 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -392,8 +392,8 @@ include(Source/CMakeVersion.cmake)
 include(CTest)
 
 # Set up test-time configuration.
-set_directory_properties(PROPERTIES
-  TEST_INCLUDE_FILE "${CMake_BINARY_DIR}/Tests/EnforceConfig.cmake")
+set_property(DIRECTORY APPEND PROPERTY
+  TEST_INCLUDE_FILES "${CMake_BINARY_DIR}/Tests/EnforceConfig.cmake")
 
 if(NOT CMake_TEST_EXTERNAL_CMAKE)
   # where to write the resulting executables and libraries
diff --git a/Tests/RunCMake/CTest/TestfileErrors.cmake b/Tests/RunCMake/CTest/TestfileErrors.cmake
index 676eb479d7..68ab6f85a4 100644
--- a/Tests/RunCMake/CTest/TestfileErrors.cmake
+++ b/Tests/RunCMake/CTest/TestfileErrors.cmake
@@ -1,3 +1,3 @@
 include(CTest)
 add_test(NAME "unreachable" COMMAND ${CMAKE_COMMAND} -E true)
-set_property(DIRECTORY PROPERTY TEST_INCLUDE_FILE ${CMAKE_CURRENT_SOURCE_DIR}/TestfileErrors-Script.cmake)
+set_property(DIRECTORY APPEND PROPERTY TEST_INCLUDE_FILES "${CMAKE_CURRENT_SOURCE_DIR}/TestfileErrors-Script.cmake")