diff --git a/tests/laborious/utils/repository/test_opc_repository.py b/tests/laborious/utils/repository/test_opc_repository.py
index ae9dd89..7369496 100644
--- a/tests/laborious/utils/repository/test_opc_repository.py
+++ b/tests/laborious/utils/repository/test_opc_repository.py
@@ -224,6 +224,24 @@ def test_write_data_get_node_failed(opc_repository):
     assert opc_repository.error_count == 1
 
 
+def test_write_data_invalid_data_type(opc_repository, mock_client):
+    opc_repository.validate_connection = MagicMock(return_value=True)
+    opc_repository.client = mock_client
+    mock_node = MagicMock()
+    mock_client.get_node.return_value = mock_node
+
+    opc_repository.write_data("ns=2;s=TestNode", 42.0, "invalid_type")
+    opc_repository.validate_connection.assert_called_once()
+    mock_client.get_node.assert_called_once_with("ns=2;s=TestNode")
+
+    opc_repository.notification_handler.build_and_send_notification.assert_called_once_with(
+        notification_id=f"OPC_WRITE_DATA_TYPE_ERROR_{opc_repository.name}",
+        message="Unsupported data type: invalid_type",
+        block="opc_repository",
+        level=NotificationLevel.ERROR
+    )
+
+
 def test_write_data(opc_repository, mock_client):
     opc_repository.validate_connection = MagicMock(return_value=True)
     opc_repository.client = mock_client