diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 3cbfb0b2..d6532f90 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -88,7 +88,7 @@ int np2_server_test_stop(void);")
 int np2_${TEST}(int argc, char *argv[]);")
     endforeach()
 
-    add_library(netopeer2_lib_test OBJECT "${TEST_SRC_DIR}/${TEST_SRC}")
+    add_library(netopeer2_lib_test OBJECT ${TEST_SRC})
     target_compile_definitions(netopeer2_lib_test PRIVATE NETOPEER2_LIB)
 
     include_directories(${TEST_BIN_DIR})
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 75c186c2..0146cc39 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -37,8 +37,8 @@ include_directories(SYSTEM ${CMOCKA_INCLUDE_DIR})
 include_directories(${CMAKE_CURRENT_SOURCE_DIR})
 include_directories(${CMAKE_CURRENT_BINARY_DIR})
 
-# base test source
-set(TEST_SRC "np2_test.c" "np2_other_client.c")
+# base test source (absolute path, used by the lib as well)
+set(TEST_SRC "${CMAKE_CURRENT_SOURCE_DIR}/np2_test.c" "${CMAKE_CURRENT_SOURCE_DIR}/np2_other_client.c")
 
 # list of all the tests
 set(TESTS test_rpc test_edit test_filter test_subscribe_filter test_subscribe_param test_parallel_sessions