diff --git a/CMakeLists.txt b/CMakeLists.txt
index e2d353abf2..4387e0e53e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -630,7 +630,7 @@ if (CMAKE_COMPILER_IS_GNUCC)
   set(CMAKE_C_FLAGS_RELEASE        "-O3 -fomit-frame-pointer"       CACHE INTERNAL "C release flags")
   set(CMAKE_C_FLAGS_RELWITHDEBINFO "-O3 -g -fno-omit-frame-pointer" CACHE INTERNAL "C release with debug info flags")
 
-  set(CMAKE_CXX_FLAGS                "-g"                             CACHE INTERNAL "default C++ compiler flags")
+  set(CMAKE_CXX_FLAGS                "-g -Wnon-virtual-dtor"          CACHE INTERNAL "default C++ compiler flags")
   set(CMAKE_CXX_FLAGS_DEBUG          "-O0 -g -D_DEBUG=1"              CACHE INTERNAL "C++ debug flags")
   set(CMAKE_CXX_FLAGS_MINSIZEREL     "-Os"                            CACHE INTERNAL "C++ minimal size flags")
   set(CMAKE_CXX_FLAGS_RELEASE        "-O3 -fomit-frame-pointer"       CACHE INTERNAL "C++ release flags")
@@ -649,7 +649,7 @@ elseif (CMAKE_COMPILER_IS_CLANG)
   set(CMAKE_C_FLAGS_RELEASE        "-O3 -fomit-frame-pointer"       CACHE INTERNAL "C release flags")
   set(CMAKE_C_FLAGS_RELWITHDEBINFO "-O3 -g -fno-omit-frame-pointer" CACHE INTERNAL "C release with debug info flags")
 
-  set(CMAKE_CXX_FLAGS                "-g"                             CACHE INTERNAL "default C++ compiler flags")
+  set(CMAKE_CXX_FLAGS                "-g -Wnon-virtual-dtor"          CACHE INTERNAL "default C++ compiler flags")
   set(CMAKE_CXX_FLAGS_DEBUG          "-O0 -g -D_DEBUG=1"              CACHE INTERNAL "C++ debug flags")
   set(CMAKE_CXX_FLAGS_MINSIZEREL     "-Os"                            CACHE INTERNAL "C++ minimal size flags")
   set(CMAKE_CXX_FLAGS_RELEASE        "-O3 -fomit-frame-pointer"       CACHE INTERNAL "C++ release flags")
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index f794ac3f5a..da22dd3d45 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -52,6 +52,11 @@ target_link_libraries(
 
 target_include_directories(arangodbtests PRIVATE
   ${INCLUDE_DIRECTORIES}
+)
+
+# add these includes as system includes because otherwise
+# the compiler will emit warnings for fakeit.hpp
+target_include_directories(arangodbtests SYSTEM PRIVATE
   ${CMAKE_SOURCE_DIR}/3rdParty/catch
   ${CMAKE_SOURCE_DIR}/3rdParty/fakeit
 )