diff --git a/Installation/cmake/modules/CGAL_SetupFlags.cmake b/Installation/cmake/modules/CGAL_SetupFlags.cmake
index 88798bba88f..7393f446139 100644
--- a/Installation/cmake/modules/CGAL_SetupFlags.cmake
+++ b/Installation/cmake/modules/CGAL_SetupFlags.cmake
@@ -57,6 +57,10 @@ if ( NOT CMAKE_BUILD_TYPE )
   endif()
 endif()
 
+if( RUNNING_CGAL_AUTO_TEST )
+  add_definitions(-DCGAL_TEST_SUITE)
+endif()
+
 if ( NOT "${CMAKE_BUILD_TYPE}" STREQUAL "Release" AND NOT "${CMAKE_BUILD_TYPE}" STREQUAL "Debug" )
   message( FATAL_ERROR "${CMAKE_BUILD_TYPE} is not a valid build type: only Release or Debug is allowed" )
 endif()
diff --git a/Installation/include/CGAL/config.h b/Installation/include/CGAL/config.h
index 4bae87ab6f5..1e592599bff 100644
--- a/Installation/include/CGAL/config.h
+++ b/Installation/include/CGAL/config.h
@@ -34,6 +34,10 @@
 #include <windows.h>
 #endif
 
+#if defined(CGAL_TEST_SUITE) && defined(NDEBUG)
+#  error The test-suite needs no NDEBUG defined
+#endif // CGAL_TEST_SUITE and NDEBUG
+
 // The following header file defines among other things  BOOST_PREVENT_MACRO_SUBSTITUTION 
 #include <boost/config.hpp>