zmq4: fix splitAddr to properly join host and port for ipv6

Fixes #83 

Co-authored-by: Sergey Egorov <sergey.egorov@teleste.com>

Author: egorse

utils.go

@@ -41,7 +41,7 @@ func splitAddr(v string) (network, addr string, err error) {
 		case "", "*":
 			host = "0.0.0.0"
 		}
-		addr = host + ":" + port
+		addr = net.JoinHostPort(host, port)
 		return network, addr, err
 
 	case "ipc":

utils_test.go

@@ -0,0 +1,56 @@
+// Copyright 2018 The go-zeromq 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 zmq4
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestSplitAddr(t *testing.T) {
+	testCases := []struct {
+		desc    string
+		v       string
+		network string
+		addr    string
+		err     error
+	}{
+		{
+			desc:    "tcp wild",
+			v:       "tcp://*:5000",
+			network: "tcp",
+			addr:    "0.0.0.0:5000",
+			err:     nil,
+		},
+		{
+			desc:    "tcp ipv4",
+			v:       "tcp://127.0.0.1:6000",
+			network: "tcp",
+			addr:    "127.0.0.1:6000",
+			err:     nil,
+		},
+		{
+			desc:    "tcp ipv6",
+			v:       "tcp://[::1]:7000",
+			network: "tcp",
+			addr:    "[::1]:7000",
+			err:     nil,
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.desc, func(t *testing.T) {
+			network, addr, err := splitAddr(tc.v)
+			if network != tc.network {
+				t.Fatalf("unexpected network: got=%v, want=%v", network, tc.network)
+			}
+			if addr != tc.addr {
+				t.Fatalf("unexpected address: got=%q, want=%q", addr, tc.addr)
+			}
+			if fmt.Sprintf("%+v", err) != fmt.Sprintf("%+v", tc.err) { // nil-safe comparison errors by value
+				t.Fatalf("unexpected error: got=%+v, want=%+v", err, tc.err)
+			}
+		})
+	}
+}