Another swag at it.
diff --git a/.appveyor.yml b/.appveyor.yml
index f71e3ae..2dcb400 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -125,4 +125,4 @@
   - cmake --build . --config %CFG% 
 
 test_script:
-  - ctest --output-on-failure --config %CFG"%
+  - ctest --output-on-failure -C %CFG%