diff --git a/erpnext/maintenance/doctype/maintenance_schedule/test_maintenance_schedule.py b/erpnext/maintenance/doctype/maintenance_schedule/test_maintenance_schedule.py
index 7539505..378d323 100644
--- a/erpnext/maintenance/doctype/maintenance_schedule/test_maintenance_schedule.py
+++ b/erpnext/maintenance/doctype/maintenance_schedule/test_maintenance_schedule.py
@@ -115,7 +115,8 @@
 		serial_item_doc.has_serial_no = 1
 		serial_item_doc.serial_no_series = "TEST.###"
 		serial_item_doc.save(ignore_permissions=True)
-	if frappe.db.exists('Serial No', {"status": "Active", "item_code": item_code}):
+	active_serials = frappe.db.get_all('Serial No', {"status": "Active", "item_code": item_code})
+	if len(active_serials) < 2:
 		make_serialized_item(item_code=item_code)
 
 def get_events(ms):