p2p/netutil: unittests for addrutil (#30439)

add unit tests for `p2p/addrutil`

---------

Co-authored-by: Martin HS <martin@swende.se>

p2p/netutil/addrutil_test.go

@@ -0,0 +1,140 @@
+// Copyright 2024 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package netutil
+
+import (
+	"net"
+	"net/netip"
+	"path/filepath"
+	"testing"
+)
+
+// customNetAddr is a custom implementation of net.Addr for testing purposes.
+type customNetAddr struct{}
+
+func (c *customNetAddr) Network() string { return "custom" }
+func (c *customNetAddr) String() string  { return "custom" }
+
+func TestAddrAddr(t *testing.T) {
+	tempDir := t.TempDir()
+	tests := []struct {
+		name string
+		addr net.Addr
+		want netip.Addr
+	}{
+		{
+			name: "IPAddr IPv4",
+			addr: &net.IPAddr{IP: net.ParseIP("192.0.2.1")},
+			want: netip.MustParseAddr("192.0.2.1"),
+		},
+		{
+			name: "IPAddr IPv6",
+			addr: &net.IPAddr{IP: net.ParseIP("2001:db8::1")},
+			want: netip.MustParseAddr("2001:db8::1"),
+		},
+		{
+			name: "TCPAddr IPv4",
+			addr: &net.TCPAddr{IP: net.ParseIP("192.0.2.1"), Port: 8080},
+			want: netip.MustParseAddr("192.0.2.1"),
+		},
+		{
+			name: "TCPAddr IPv6",
+			addr: &net.TCPAddr{IP: net.ParseIP("2001:db8::1"), Port: 8080},
+			want: netip.MustParseAddr("2001:db8::1"),
+		},
+		{
+			name: "UDPAddr IPv4",
+			addr: &net.UDPAddr{IP: net.ParseIP("192.0.2.1"), Port: 8080},
+			want: netip.MustParseAddr("192.0.2.1"),
+		},
+		{
+			name: "UDPAddr IPv6",
+			addr: &net.UDPAddr{IP: net.ParseIP("2001:db8::1"), Port: 8080},
+			want: netip.MustParseAddr("2001:db8::1"),
+		},
+		{
+			name: "Unsupported Addr type",
+			addr: &net.UnixAddr{Name: filepath.Join(tempDir, "test.sock"), Net: "unix"},
+			want: netip.Addr{},
+		},
+		{
+			name: "Nil input",
+			addr: nil,
+			want: netip.Addr{},
+		},
+		{
+			name: "Custom net.Addr implementation",
+			addr: &customNetAddr{},
+			want: netip.Addr{},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := AddrAddr(tt.addr); got != tt.want {
+				t.Errorf("AddrAddr() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestIPToAddr(t *testing.T) {
+	tests := []struct {
+		name string
+		ip   net.IP
+		want netip.Addr
+	}{
+		{
+			name: "IPv4",
+			ip:   net.ParseIP("192.0.2.1"),
+			want: netip.MustParseAddr("192.0.2.1"),
+		},
+		{
+			name: "IPv6",
+			ip:   net.ParseIP("2001:db8::1"),
+			want: netip.MustParseAddr("2001:db8::1"),
+		},
+		{
+			name: "Invalid IP",
+			ip:   net.IP{1, 2, 3},
+			want: netip.Addr{},
+		},
+		{
+			name: "Invalid IP (5 octets)",
+			ip:   net.IP{192, 0, 2, 1, 1},
+			want: netip.Addr{},
+		},
+		{
+			name: "IPv4-mapped IPv6",
+			ip:   net.ParseIP("::ffff:192.0.2.1"),
+			want: netip.MustParseAddr("192.0.2.1"),
+		},
+		{
+			name: "Nil input",
+			ip:   nil,
+			want: netip.Addr{},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := IPToAddr(tt.ip); got != tt.want {
+				t.Errorf("IPToAddr() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}