diff --git a/Tests/Module/WriteCompilerDetectionHeader/CMakeLists.txt b/Tests/Module/WriteCompilerDetectionHeader/CMakeLists.txt
index b5e46c00b..78c4a6aaa 100644
--- a/Tests/Module/WriteCompilerDetectionHeader/CMakeLists.txt
+++ b/Tests/Module/WriteCompilerDetectionHeader/CMakeLists.txt
@@ -71,7 +71,7 @@ if (CMAKE_C_COMPILER_ID STREQUAL "GNU"
     OR CMAKE_C_COMPILER_ID STREQUAL "Clang"
     OR CMAKE_C_COMPILER_ID STREQUAL "AppleClang")
   add_executable(C_undefined c_undefined.c)
-  set_property(TARGET C_undefined PROPERTY CXX_STANDARD 90)
+  set_property(TARGET C_undefined PROPERTY C_STANDARD 90)
   target_compile_options(C_undefined PRIVATE -Werror=undef)
 endif()
 
diff --git a/Tests/Module/WriteCompilerDetectionHeader/main.cpp b/Tests/Module/WriteCompilerDetectionHeader/main.cpp
index 82b219163..192094c1b 100644
--- a/Tests/Module/WriteCompilerDetectionHeader/main.cpp
+++ b/Tests/Module/WriteCompilerDetectionHeader/main.cpp
@@ -4,6 +4,10 @@
 #define PREFIX TEST
 #include "compile_tests.h"
 
+#ifdef TEST_COMPILER_C_STATIC_ASSERT
+#error Expect no C features defined
+#endif
+
 int main()
 {
   return 0;
diff --git a/Tests/Module/WriteCompilerDetectionHeader/multi_files.cpp b/Tests/Module/WriteCompilerDetectionHeader/multi_files.cpp
index ca298231d..1635091cb 100644
--- a/Tests/Module/WriteCompilerDetectionHeader/multi_files.cpp
+++ b/Tests/Module/WriteCompilerDetectionHeader/multi_files.cpp
@@ -4,6 +4,10 @@
 #define PREFIX MULTI
 #include "compile_tests.h"
 
+#ifdef MULTI_COMPILER_C_STATIC_ASSERT
+#error Expect no C features defined
+#endif
+
 int main()
 {
   return 0;