diff --git a/CMakeLists.txt b/CMakeLists.txt
index a8fb64b..6687b56 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -679,11 +679,11 @@
     endif ()
 
     foreach (test_name ${unit_tests})
+        cmake_path(SET _UT_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/tests/unit_tests/openvpn)
         # test_networking needs special environment
         if (NOT ${test_name} STREQUAL "test_networking")
             add_test(${test_name} ${test_name})
             # for compat with autotools make check
-            set(_UT_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/tests/unit_tests/openvpn)
             set_tests_properties(${test_name} PROPERTIES
                 ENVIRONMENT "srcdir=${_UT_SOURCE_DIR}")
         endif ()
@@ -703,7 +703,7 @@
 
         # for compat with IDEs like Clion that ignore the tests properties
         # for the environment variable srcdir when running tests as fallback
-        target_compile_definitions(${test_name} PRIVATE "-DUNIT_TEST_SOURCEDIR=\"${CMAKE_SOURCE_DIR}/tests/unit_tests/openvpn\"")
+        target_compile_definitions(${test_name} PRIVATE "UNIT_TEST_SOURCEDIR=\"${_UT_SOURCE_DIR}\"")
 
         if (NOT ${test_name} STREQUAL "test_buffer")
             target_sources(${test_name} PRIVATE