diff --git a/server_addr_book_test.go b/server_addr_book_test.go
new file mode 100644
index 0000000..5e9581a
--- /dev/null
+++ b/server_addr_book_test.go
@@ -0,0 +1,165 @@
+package main
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/libp2p/go-libp2p"
+	"github.com/libp2p/go-libp2p/core/event"
+	"github.com/libp2p/go-libp2p/core/network"
+	"github.com/libp2p/go-libp2p/core/peer"
+	ma "github.com/multiformats/go-multiaddr"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCachedAddrBook(t *testing.T) {
+	// Create a new cached address book
+	cab := newCachedAddrBook()
+	require.NotNil(t, cab)
+	require.NotNil(t, cab.peers)
+	require.NotNil(t, cab.addrBook)
+}
+
+func TestGetCachedAddrs(t *testing.T) {
+	cab := newCachedAddrBook()
+
+	// Create a test peer with new PeerID
+	testPeer, err := peer.Decode("12D3KooWCZ67sU8oCvKd82Y6c9NgpqgoZYuZEUcg4upHCjK3n1aj")
+	require.NoError(t, err)
+
+	// Add test addresses
+	addr1, _ := ma.NewMultiaddr("/ip4/127.0.0.1/tcp/1234")
+	addr2, _ := ma.NewMultiaddr("/ip4/127.0.0.1/tcp/5678")
+	cab.addrBook.AddAddrs(testPeer, []ma.Multiaddr{addr1, addr2}, time.Hour)
+
+	// Initialize peer state
+	cab.peers[testPeer] = &peerState{}
+
+	// Test getting addresses
+	addrs := cab.GetCachedAddrs(&testPeer)
+	assert.Len(t, addrs, 2)
+
+	// Verify return count and time were updated
+	assert.Equal(t, 1, cab.peers[testPeer].returnCount)
+	assert.False(t, cab.peers[testPeer].lastReturnTime.IsZero())
+}
+
+func TestBackground(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	// Create a test libp2p host
+	h, err := libp2p.New(libp2p.ListenAddrStrings("/ip4/127.0.0.1/tcp/0"))
+	require.NoError(t, err)
+	defer h.Close()
+
+	em, err := h.EventBus().Emitter(new(event.EvtPeerIdentificationCompleted))
+	require.NoError(t, err)
+	defer em.Close()
+
+	cab := newCachedAddrBook()
+
+	// Create a channel to signal when background processing is ready
+	ready := make(chan struct{})
+
+	// Start background process with ready signal
+	go func() {
+		// Signal ready before starting background process
+		close(ready)
+		cab.background(ctx, h)
+	}()
+
+	// Wait for background process to start
+	<-ready
+
+	// Create a test peer with new PeerID
+	testPeer, err := peer.Decode("12D3KooWCZ67sU8oCvKd82Y6c9NgpqgoZYuZEUcg4upHCjK3n1aj")
+	require.NoError(t, err)
+
+	// Simulate peer identification event
+	addr, _ := ma.NewMultiaddr("/ip4/127.0.0.1/tcp/1234")
+
+	// Use a channel to wait for event processing
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		// Check periodically until the peer is added or timeout (after 50 * 10ms)
+		for i := 0; i < 50; i++ {
+			cab.mu.RLock()
+			peerState, exists := cab.peers[testPeer]
+			if exists {
+				assert.Equal(t, addr, peerState.lastConnAddr)
+				cab.mu.RUnlock()
+				return
+			}
+			cab.mu.RUnlock()
+			time.Sleep(10 * time.Millisecond)
+		}
+	}()
+
+	// Emit the event after setting up the waiter
+	err = em.Emit(event.EvtPeerIdentificationCompleted{
+		Peer: testPeer,
+		Conn: &mockConnection{
+			remoteAddr: addr,
+		},
+		ListenAddrs: []ma.Multiaddr{addr},
+	})
+	require.NoError(t, err)
+
+	// Wait for processing with timeout
+	select {
+	case <-done:
+		// Success case - continue to verification
+	case <-time.After(time.Second):
+		t.Fatal("timeout waiting for peer to be added")
+	}
+
+	// Verify peer was added
+	cab.mu.RLock()
+	peerState, exists := cab.peers[testPeer]
+	assert.True(t, exists)
+	assert.NotNil(t, peerState)
+	assert.Equal(t, addr, peerState.lastConnAddr)
+	cab.mu.RUnlock()
+}
+
+func TestProbePeers(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	// Create a test libp2p host
+	h, err := libp2p.New()
+	require.NoError(t, err)
+	defer h.Close()
+
+	cab := newCachedAddrBook()
+
+	// Add a test peer with some addresses
+	testPeer, _ := peer.Decode("12D3KooWCZ67sU8oCvKd82Y6c9NgpqgoZYuZEUcg4upHCjK3n1aj")
+	addr, _ := ma.NewMultiaddr("/ip4/127.0.0.1/tcp/1234")
+	cab.addrBook.AddAddrs(testPeer, []ma.Multiaddr{addr}, time.Hour)
+
+	// Initialize peer state with old connection time
+	cab.peers[testPeer] = &peerState{
+		lastConnTime: time.Now().Add(-2 * PeerProbeThreshold),
+	}
+
+	// Run probe
+	cab.probePeers(ctx, h)
+
+	// Verify connect failures increased (since connection will fail in test)
+	assert.Equal(t, 1, cab.peers[testPeer].connectFailures)
+}
+
+// Mock connection for testing
+type mockConnection struct {
+	network.Conn
+	remoteAddr ma.Multiaddr
+}
+
+func (mc *mockConnection) RemoteMultiaddr() ma.Multiaddr {
+	return mc.remoteAddr
+}