diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7bf6abb..053fd7b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -140,7 +140,7 @@
     RUNTIME DESTINATION bin
   )
 
-  if (EXISTS "tests")
+  if (IS_DIRECTORY "${PROJECT_SOURCE_DIR}/tests")
     enable_testing()
 
     if(BUILD_TESTING)