diff --git a/loop/port_monitor_test.go b/loop/port_monitor_test.go
new file mode 100644
index 0000000..8f474e0
--- /dev/null
+++ b/loop/port_monitor_test.go
@@ -0,0 +1,133 @@
+package loop
+
+import (
+	"context"
+	"testing"
+)
+
+// TestPortMonitoring tests the port monitoring functionality
+func TestPortMonitoring(t *testing.T) {
+	// Test with ss output format
+	ssOutput := `Netid State  Recv-Q Send-Q Local Address:Port  Peer Address:PortProcess
+tcp   LISTEN 0      1024       127.0.0.1:40975      0.0.0.0:*          
+tcp   LISTEN 0      4096               *:22               *:*          
+tcp   LISTEN 0      4096               *:80               *:*          
+udp   UNCONN 0      0               127.0.0.1:123            0.0.0.0:*          
+`
+
+	expected := map[string]bool{
+		"tcp:127.0.0.1:40975": true,
+		"tcp:*:22":            true,
+		"tcp:*:80":            true,
+	}
+
+	result := parseSSPorts(ssOutput)
+
+	// Check that all expected ports are found
+	for port := range expected {
+		if !result[port] {
+			t.Errorf("Expected port %s not found in ss parsed output", port)
+		}
+	}
+
+	// Check that UDP port is not included (since it's UNCONN, not LISTEN)
+	if result["udp:127.0.0.1:123"] {
+		t.Errorf("UDP UNCONN port should not be included in listening ports")
+	}
+
+	// Check that no extra ports are found
+	for port := range result {
+		if !expected[port] {
+			t.Errorf("Unexpected port %s found in parsed output", port)
+		}
+	}
+}
+
+// TestPortMonitoringLogDifferences tests the port difference logging
+func TestPortMonitoringLogDifferences(t *testing.T) {
+	ctx := context.Background()
+
+	oldPorts := `Netid State  Recv-Q Send-Q Local Address:Port  Peer Address:PortProcess
+tcp   LISTEN 0      4096               *:22               *:*          
+tcp   LISTEN 0      1024       127.0.0.1:8080      0.0.0.0:*          
+`
+
+	newPorts := `Netid State  Recv-Q Send-Q Local Address:Port  Peer Address:PortProcess
+tcp   LISTEN 0      4096               *:22               *:*          
+tcp   LISTEN 0      1024       127.0.0.1:9090      0.0.0.0:*          
+`
+
+	// Create a port monitor to test the logPortDifferences method
+	pm := NewPortMonitor()
+
+	// This test mainly ensures the method doesn't panic and processes the differences
+	// The actual logging output would need to be captured via a test logger to verify fully
+	pm.logPortDifferences(ctx, oldPorts, newPorts)
+
+	// Test with no differences
+	pm.logPortDifferences(ctx, oldPorts, oldPorts)
+}
+
+// TestPortMonitorCreation tests creating a new port monitor
+func TestPortMonitorCreation(t *testing.T) {
+	pm := NewPortMonitor()
+	if pm == nil {
+		t.Error("NewPortMonitor() returned nil")
+	}
+
+	// Verify initial state
+	pm.mu.Lock()
+	defer pm.mu.Unlock()
+	if pm.lastPorts != "" {
+		t.Error("NewPortMonitor() should have empty lastPorts initially")
+	}
+}
+
+// TestParseSSPortsEdgeCases tests edge cases in ss output parsing
+func TestParseSSPortsEdgeCases(t *testing.T) {
+	tests := []struct {
+		name     string
+		output   string
+		expected map[string]bool
+	}{
+		{
+			name:     "empty output",
+			output:   "",
+			expected: map[string]bool{},
+		},
+		{
+			name:     "header only",
+			output:   "Netid State  Recv-Q Send-Q Local Address:Port  Peer Address:PortProcess",
+			expected: map[string]bool{},
+		},
+		{
+			name:     "non-listen states filtered out",
+			output:   "tcp   ESTAB  0      0       127.0.0.1:8080      127.0.0.1:45678\nudp   UNCONN 0      0       127.0.0.1:123       0.0.0.0:*",
+			expected: map[string]bool{},
+		},
+		{
+			name:     "insufficient fields",
+			output:   "tcp LISTEN 0",
+			expected: map[string]bool{},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			result := parseSSPorts(test.output)
+			if len(result) != len(test.expected) {
+				t.Errorf("Expected %d ports, got %d", len(test.expected), len(result))
+			}
+			for port := range test.expected {
+				if !result[port] {
+					t.Errorf("Expected port %s not found", port)
+				}
+			}
+			for port := range result {
+				if !test.expected[port] {
+					t.Errorf("Unexpected port %s found", port)
+				}
+			}
+		})
+	}
+}