return 520 if parameters are not found

internal/wrphandlers/mocktr181/handler.go

@@ -154,6 +154,7 @@ func (h Handler) HandleWrp(msg wrp.Message) error {
 
 func (h Handler) get(names []string) (int64, []byte, error) {
 	result := Tr181Payload{}
+	statusCode := int64(http.StatusOK)
 
 	for _, name := range names {
 		for _, mockParameter := range h.parameters {
@@ -173,7 +174,11 @@ func (h Handler) get(names []string) (int64, []byte, error) {
 		return http.StatusInternalServerError, payload, errors.Join(ErrInvalidResponsePayload, err)
 	}
 
-	return http.StatusOK, payload, nil
+	if len(result.Parameters) == 0 {
+		statusCode = int64(520)
+	}
+
+	return statusCode, payload, nil
 }
 
 func (h Handler) set(parameters []Parameter) int64 {

internal/wrphandlers/mocktr181/handler_test.go

@@ -44,6 +44,25 @@ func TestHandler_HandleWrp(t *testing.T) {
 				a.True(h.Enabled())
 				return nil
 			},
+		}, {
+			description:     "get with no mataching parameter",
+			egressCallCount: 1,
+			expectedErr:     nil,
+			msg: wrp.Message{
+				Type:        wrp.SimpleEventMessageType,
+				Source:      "dns:tr1d1um.example.com/service/ignored",
+				Destination: "event:event_1/ignored",
+				Payload:     []byte("{\"command\":\"GET\",\"names\":[\"NoSuchParameter\"]}"),
+			},
+			validate: func(a *assert.Assertions, msg wrp.Message, h *Handler) error {
+				a.Equal(int64(520), *msg.Status)
+				var result Tr181Payload
+				err := json.Unmarshal(msg.Payload, &result)
+				a.NoError(err)
+				a.Equal(0, len(result.Parameters))
+				a.True(h.Enabled())
+				return nil
+			},
 		}, {
 			description:     "set, success",
 			egressCallCount: 1,