diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 355013a25b..eb9d9cc7bb 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -29,7 +29,7 @@ if(MSVC)
 endif()
 
 if(WIN32)
-    add_definitions(-DCOIN_DLL)
+    add_definitions(-DCOIN_DLL -D_USE_MATH_DEFINES)
 endif(WIN32)
 
 if(NOT BUILD_DYNAMIC_LINK_PYTHON)