diff --git a/tests/4-opt/CMakeLists.txt b/tests/4-opt/CMakeLists.txt
index ce6155e18ddb8e47e28e0a8f92a83302c641ed74..2b745de31649bfa19ec63162fcffeba188420eee 100644
--- a/tests/4-opt/CMakeLists.txt
+++ b/tests/4-opt/CMakeLists.txt
@@ -3,6 +3,11 @@ add_executable(
     eval_lab4.cpp
 )
 
+if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU" AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS "9.0")
+    target_link_libraries(eval_lab4 PRIVATE stdc++fs)
+elseif (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS "9.0")
+    target_link_libraries(eval_lab4 PRIVATE c++fs)
+endif()
 
 install(
     TARGETS eval_lab4