diff --git a/.appveyor.yml b/.appveyor.yml
index 9f319ab..e45645c 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -7,7 +7,7 @@ environment:
     PREFIX: c:\usr_msvc
     MSVC:
     MINGW32: rem
-  - CMAKE_ARGS: -DCMAKE_C_COMPILER=mingw32-cc -DCMAKE_CXX_COMPILER=mingw32-c++ -DCMAKE_MAKE_PROGRAM=mingw32-make.exe -DCMAKE_VERBOSE_MAKEFILE=ON -DSDL2PP_ENABLE_LIVE_TESTS=OFF -G "MinGW Makefiles"
+  - CMAKE_ARGS: -DCMAKE_C_COMPILER=mingw32-cc -DCMAKE_CXX_COMPILER=mingw32-c++ -DCMAKE_MAKE_PROGRAM=mingw32-make.exe -DCMAKE_VERBOSE_MAKEFILE=ON -DSDL2PP_ENABLE_LIVE_TESTS=OFF -DSDL2PP_WITH_WERROR=YES -G "MinGW Makefiles"
     PREFIX: c:\usr_mingw32
     MINGW32:
     MSVC: rem