diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 94c9f909..f23a056b 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -33,7 +33,7 @@ if(NETOPEER2_LIB_TESTS)
 /**
  * @brief Directory where to put test_files for the tests to work.
  */
-#define NP2_TEST_FILE_DIR \"${CMAKE_CURRENT_SOURCE_DIR}/modules\"
+#define NP2_TEST_FILE_DIR \"${TEST_MODULE_DIR}\"
 ")
     set(NETOPEER2_TESTS_FUNC "${NETOPEER2_TESTS_FUNC}
 /**
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 47154c83..f76b7167 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -106,3 +106,4 @@ set(TESTS ${TESTS} PARENT_SCOPE)
 set(TEST_SRC ${TEST_SRC} PARENT_SCOPE)
 set(TEST_SRC_DIR ${CMAKE_CURRENT_SOURCE_DIR} PARENT_SCOPE)
 set(TEST_BIN_DIR ${CMAKE_CURRENT_BINARY_DIR} PARENT_SCOPE)
+set(TEST_MODULE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/modules PARENT_SCOPE)