Add test for dnsMapsEqual.

Exercises most cases in the function.

Signed-off-by: Denton Gentry <dgentry@tailscale.com>

ipn/local_test.go

@@ -0,0 +1,105 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ipn
+
+import (
+	"inet.af/netaddr"
+	"tailscale.com/control/controlclient"
+	"tailscale.com/tailcfg"
+	"testing"
+)
+
+func TestNetworkMapCompare(t *testing.T) {
+	prefix1, err := netaddr.ParseIPPrefix("192.168.0.0/24")
+	if err != nil {
+		t.Fatal(err)
+	}
+	node1 := &tailcfg.Node{Addresses: []netaddr.IPPrefix{prefix1}}
+
+	prefix2, err := netaddr.ParseIPPrefix("10.0.0.0/8")
+	if err != nil {
+		t.Fatal(err)
+	}
+	node2 := &tailcfg.Node{Addresses: []netaddr.IPPrefix{prefix2}}
+
+	tests := []struct {
+		a, b *controlclient.NetworkMap
+		want bool
+	}{
+		{
+			nil,
+			nil,
+			true,
+		},
+		{
+			&controlclient.NetworkMap{},
+			nil,
+			false,
+		},
+		{
+			nil,
+			&controlclient.NetworkMap{},
+			false,
+		},
+		{
+			&controlclient.NetworkMap{},
+			&controlclient.NetworkMap{},
+			true,
+		},
+		{
+			&controlclient.NetworkMap{Name: "map1"},
+			&controlclient.NetworkMap{Name: "map1"},
+			true,
+		},
+		{
+			&controlclient.NetworkMap{Name: "map1"},
+			&controlclient.NetworkMap{Name: "map2"},
+			false,
+		},
+		{
+			&controlclient.NetworkMap{Peers: []*tailcfg.Node{}},
+			&controlclient.NetworkMap{Peers: []*tailcfg.Node{}},
+			true,
+		},
+		{
+			// length of Peers list differs
+			&controlclient.NetworkMap{Peers: []*tailcfg.Node{{}}},
+			&controlclient.NetworkMap{Peers: []*tailcfg.Node{}},
+			false,
+		},
+		{
+			&controlclient.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{Name: "A"}}},
+			&controlclient.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{Name: "A"}}},
+			true,
+		},
+		{
+			&controlclient.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{Name: "A"}}},
+			&controlclient.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{Name: "B"}}},
+			false,
+		},
+		{
+			&controlclient.NetworkMap{Peers: []*tailcfg.Node{node1, node1}},
+			&controlclient.NetworkMap{Peers: []*tailcfg.Node{node1, node1}},
+			true,
+		},
+		{
+			&controlclient.NetworkMap{Peers: []*tailcfg.Node{node1, node1}},
+			&controlclient.NetworkMap{Peers: []*tailcfg.Node{node1, node2}},
+			false,
+		},
+		{
+			// User field is not checked.
+			&controlclient.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{User: 0}}},
+			&controlclient.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{User: 1}}},
+			true,
+		},
+	}
+	for i, tt := range tests {
+		got := dnsMapsEqual(tt.a, tt.b)
+		if got != tt.want {
+			t.Errorf("%d. Equal = %v; want %v", i, got, tt.want)
+		}
+	}
+}