pkg/netutil: fix false negative comparison

Sort the resolved URLs before DeepEqual, so it will not compare URLs
that may be out of order due to resolution.

pkg/netutil/netutil.go

@@ -20,9 +20,11 @@ import (
 	"net/http"
 	"net/url"
 	"reflect"
+	"sort"
 	"strings"
 
 	"github.com/coreos/etcd/Godeps/_workspace/src/github.com/coreos/pkg/capnslog"
+	"github.com/coreos/etcd/pkg/types"
 )
 
 var (
@@ -67,15 +69,12 @@ func URLsEqual(a []url.URL, b []url.URL) bool {
 	if len(a) != len(b) {
 		return false
 	}
-	for i, urlA := range a {
-		urlB := b[i]
-
-		if !reflect.DeepEqual(urlA, urlB) {
-			urls := []url.URL{urlA, urlB}
-			ResolveTCPAddrs(urls)
-			if !reflect.DeepEqual(urls[0], urls[1]) {
-				return false
-			}
+	ResolveTCPAddrs(a, b)
+	sort.Sort(types.URLs(a))
+	sort.Sort(types.URLs(b))
+	for i := range a {
+		if !reflect.DeepEqual(a[i], b[i]) {
+			return false
 		}
 	}
 

pkg/netutil/netutil_test.go

@@ -139,16 +139,21 @@ func TestResolveTCPAddrs(t *testing.T) {
 
 func TestURLsEqual(t *testing.T) {
 	defer func() { resolveTCPAddr = net.ResolveTCPAddr }()
+	hostm := map[string]string{
+		"example.com": "10.0.10.1",
+		"first.com":   "10.0.11.1",
+		"second.com":  "10.0.11.2",
+	}
 	resolveTCPAddr = func(network, addr string) (*net.TCPAddr, error) {
 		host, port, err := net.SplitHostPort(addr)
-		if host != "example.com" {
+		if _, ok := hostm[host]; !ok {
 			return nil, errors.New("cannot resolve host.")
 		}
 		i, err := strconv.Atoi(port)
 		if err != nil {
 			return nil, err
 		}
-		return &net.TCPAddr{IP: net.ParseIP("10.0.10.1"), Port: i, Zone: ""}, nil
+		return &net.TCPAddr{IP: net.ParseIP(hostm[host]), Port: i, Zone: ""}, nil
 	}
 
 	tests := []struct {
@@ -226,6 +231,16 @@ func TestURLsEqual(t *testing.T) {
 			b:      []url.URL{{Scheme: "http", Host: "10.0.0.1:2379"}, {Scheme: "http", Host: "127.0.0.1:2380"}},
 			expect: false,
 		},
+		{
+			a:      []url.URL{{Scheme: "http", Host: "first.com:2379"}, {Scheme: "http", Host: "second.com:2380"}},
+			b:      []url.URL{{Scheme: "http", Host: "10.0.11.1:2379"}, {Scheme: "http", Host: "10.0.11.2:2380"}},
+			expect: true,
+		},
+		{
+			a:      []url.URL{{Scheme: "http", Host: "second.com:2380"}, {Scheme: "http", Host: "first.com:2379"}},
+			b:      []url.URL{{Scheme: "http", Host: "10.0.11.1:2379"}, {Scheme: "http", Host: "10.0.11.2:2380"}},
+			expect: true,
+		},
 	}
 
 	for _, test := range tests {