diff --git a/controller_manager/CMakeLists.txt b/controller_manager/CMakeLists.txt
index a1a98bc59a..6e004ffc4a 100644
--- a/controller_manager/CMakeLists.txt
+++ b/controller_manager/CMakeLists.txt
@@ -195,7 +195,7 @@ if(BUILD_TESTING)
   )
 
   ament_add_gmock(test_hardware_spawner
-    test/test_hardware_spawner
+    test/test_hardware_spawner.cpp
     TIMEOUT 120
   )
   target_link_libraries(test_hardware_spawner