diff --git a/monkey/tests/unit_tests/monkey_island/cc/agent_event_handlers/test_scan_event_handler.py b/monkey/tests/unit_tests/monkey_island/cc/agent_event_handlers/test_scan_event_handler.py
index c2325ed45..82ede960f 100644
--- a/monkey/tests/unit_tests/monkey_island/cc/agent_event_handlers/test_scan_event_handler.py
+++ b/monkey/tests/unit_tests/monkey_island/cc/agent_event_handlers/test_scan_event_handler.py
@@ -267,7 +267,7 @@ def test_machine_not_upserted_if_existing_machine_has_os(
 ):
     machine_with_os = TARGET_MACHINE
     machine_with_os.operating_system = OperatingSystem.WINDOWS
-    machine_repository.get_machine_by_ip = MagicMock(return_value=machine_with_os)
+    machine_repository.get_machines_by_ip = MagicMock(return_value=[machine_with_os])
 
     scan_event_handler.handle_ping_scan_event(PING_SCAN_EVENT)