chore: Add simple unit test for encoding and decoding PDUs

ngap_test.go

@@ -0,0 +1,97 @@
+// Copyright 2024 Canonical, Ltd.
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package ngap_test
+
+import (
+	"testing"
+
+	"github.com/omec-project/aper"
+	"github.com/omec-project/ngap"
+	"github.com/omec-project/ngap/ngapType"
+)
+
+// globalRANIDIE for MCC 208, MNC 93
+var globalRANIDIE ngapType.NGSetupRequestIEs = ngapType.NGSetupRequestIEs{
+	Id:          ngapType.ProtocolIEID{Value: ngapType.ProtocolIEIDGlobalRANNodeID},
+	Criticality: ngapType.Criticality{Value: ngapType.CriticalityPresentReject},
+	Value: ngapType.NGSetupRequestIEsValue{
+		Present: ngapType.GlobalRANNodeIDPresentGlobalGNBID,
+		GlobalRANNodeID: &ngapType.GlobalRANNodeID{
+			Present: ngapType.GlobalRANNodeIDPresentGlobalGNBID,
+			GlobalGNBID: &ngapType.GlobalGNBID{
+				PLMNIdentity: ngapType.PLMNIdentity{Value: aper.OctetString{0x02, 0xF8, 0x39}},
+				GNBID: ngapType.GNBID{
+					Present: ngapType.GNBIDPresentGNBID,
+					GNBID: &aper.BitString{
+						Bytes:     []byte{0x00, 0x01, 0x02},
+						BitLength: 24,
+					},
+				},
+			},
+		},
+	},
+}
+
+func TestSimplePDUEncoding(t *testing.T) {
+	// NGSetupRequest PDU
+	pdu := ngapType.NGAPPDU{
+		Present: ngapType.NGAPPDUPresentInitiatingMessage,
+		InitiatingMessage: &ngapType.InitiatingMessage{
+			ProcedureCode: ngapType.ProcedureCode{Value: ngapType.ProcedureCodeNGSetup},
+			Criticality:   ngapType.Criticality{Value: ngapType.CriticalityPresentReject},
+			Value: ngapType.InitiatingMessageValue{
+				Present: ngapType.InitiatingMessagePresentNGSetupRequest,
+				NGSetupRequest: &ngapType.NGSetupRequest{
+					ProtocolIEs: ngapType.ProtocolIEContainerNGSetupRequestIEs{
+						List: []ngapType.NGSetupRequestIEs{
+							globalRANIDIE,
+						},
+					},
+				},
+			},
+		},
+	}
+
+	result, err := ngap.Encoder(pdu)
+	if err != nil {
+		t.Errorf("Could not encode simple PDU: %v; got error: %v\n", pdu, err)
+	}
+
+	expected := []byte{
+		0x00, 0x15, 0x00, 0x0F, 0x00, 0x00, 0x01, 0x00, 0x1B, 0x00,
+		0x08, 0x00, 0x02, 0xF8, 0x39, 0x10, 0x00, 0x01, 0x02,
+	}
+
+	if len(result) != len(expected) {
+		t.Errorf("Got wrong result length: %v\n", len(result))
+	}
+
+	for i, b := range result {
+		if b != expected[i] {
+			t.Errorf("Byte %d was %v, expected %v\n", i, b, expected[i])
+		}
+	}
+}
+
+func TestSimplePDUDecoding(t *testing.T) {
+	// ASN.1 PER encoded PDU
+	pdu_bytes := []byte{
+		0x00, 0x15, 0x00, 0x0F, 0x00, 0x00, 0x01, 0x00, 0x1B, 0x00,
+		0x08, 0x00, 0x02, 0xF8, 0x39, 0x10, 0x00, 0x01, 0x02,
+	}
+
+	pdu, err := ngap.Decoder(pdu_bytes)
+	if err != nil {
+		t.Errorf("Could not decode simple PDU bytes: %v; got error: %v\n", pdu_bytes, err)
+	}
+
+	ie := pdu.InitiatingMessage.Value.NGSetupRequest.ProtocolIEs.List[0]
+	plmn := ie.Value.GlobalRANNodeID.GlobalGNBID.PLMNIdentity.Value
+
+	if len(plmn) != 3 || plmn[0] != 0x02 || plmn[1] != 0xF8 || plmn[2] != 0x39 {
+		t.Errorf("Failed decoding simple PDU: %v; Expected PLMN: %v, got %v\n",
+			pdu_bytes, []byte{0x02, 0xF8, 0x39}, plmn)
+	}
+}