test(transport): add integration test for handleSniffer

Author: vasyl-ks

backend/pkg/transport/transport_test.go

@@ -7,18 +7,23 @@ import (
 	"fmt"
 	"io"
 	"net"
+	"os"
 	"strings"
 	"sync"
 	"testing"
 	"time"
 
 	"github.com/HyperloopUPV-H8/h9-backend/pkg/abstraction"
+	"github.com/HyperloopUPV-H8/h9-backend/pkg/transport/network/sniffer"
 	"github.com/HyperloopUPV-H8/h9-backend/pkg/transport/network/tcp"
 	"github.com/HyperloopUPV-H8/h9-backend/pkg/transport/network/tftp"
-	tftpv3 "github.com/pin/tftp/v3"
 	"github.com/HyperloopUPV-H8/h9-backend/pkg/transport/network/udp"
 	"github.com/HyperloopUPV-H8/h9-backend/pkg/transport/packet/data"
 	"github.com/HyperloopUPV-H8/h9-backend/pkg/transport/presentation"
+	"github.com/google/gopacket/layers"
+	"github.com/google/gopacket/pcap"
+	"github.com/google/gopacket/pcapgo"
+	tftpv3 "github.com/pin/tftp/v3"
 	"github.com/rs/zerolog"
 )
 
@@ -1065,6 +1070,42 @@ func TestHandleFileWriteRead_ErrorPath(t *testing.T) {
 	}
 }
 
+func TestHandleSniffer_Dispatches(t *testing.T) {
+	tr, api := createTestTransport(t)
+
+	// empty pcap (header only) to drive HandleSniffer through EOF path
+	tmp, err := os.CreateTemp("", "sniffer*.pcap")
+	if err != nil {
+		t.Fatalf("failed to create temp file: %v", err)
+	}
+	writer := pcapgo.NewWriter(tmp)
+	if err := writer.WriteFileHeader(65535, layers.LinkTypeEthernet); err != nil {
+		t.Fatalf("write header failed: %v", err)
+	}
+	tmp.Close()
+
+	handle, err := pcap.OpenOffline(tmp.Name())
+	if err != nil {
+		t.Fatalf("failed to open pcap: %v", err)
+	}
+	sn := sniffer.New(handle, nil, defaultLogger())
+
+	done := make(chan struct{})
+	go func() {
+		tr.HandleSniffer(sn)
+		close(done)
+	}()
+
+	select {
+	case <-done:
+	case <-time.After(2 * time.Second):
+		t.Fatalf("HandleSniffer did not return on EOF")
+	}
+
+	// No notifications expected; just ensure no panic/block.
+	_ = api
+}
+
 // Helper function to mimic errors.As behavior
 func ErrorAs(err error, target interface{}) bool {
 	switch target := target.(type) {