1 files changed, 69 insertions, 0 deletions
diff --git a/src/net/udpsock_plan9_test.go b/src/net/udpsock_plan9_test.go
new file mode 100644
index 0000000..3febfcc
--- /dev/null
+++ b/src/net/udpsock_plan9_test.go
@@ -0,0 +1,69 @@
+// Copyright 2016 The Go 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 net
+
+import (
+	"internal/testenv"
+	"runtime"
+	"testing"
+)
+
+func TestListenMulticastUDP(t *testing.T) {
+	testenv.MustHaveExternalNetwork(t)
+
+	ifcs, err := Interfaces()
+	if err != nil {
+		t.Skip(err.Error())
+	}
+	if len(ifcs) == 0 {
+		t.Skip("no network interfaces found")
+	}
+
+	var mifc *Interface
+	for _, ifc := range ifcs {
+		if ifc.Flags&FlagUp|FlagMulticast != FlagUp|FlagMulticast {
+			continue
+		}
+		mifc = &ifc
+		break
+	}
+
+	if mifc == nil {
+		t.Skipf("no multicast interfaces found")
+	}
+
+	c1, err := ListenMulticastUDP("udp4", mifc, &UDPAddr{IP: ParseIP("224.0.0.254")})
+	if err != nil {
+		t.Fatalf("multicast not working on %s: %v", runtime.GOOS, err)
+	}
+	c1addr := c1.LocalAddr().(*UDPAddr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c1.Close()
+
+	c2, err := ListenUDP("udp4", &UDPAddr{IP: IPv4zero, Port: 0})
+	c2addr := c2.LocalAddr().(*UDPAddr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c2.Close()
+
+	n, err := c2.WriteToUDP([]byte("data"), c1addr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if n != 4 {
+		t.Fatalf("got %d; want 4", n)
+	}
+
+	n, err = c1.WriteToUDP([]byte("data"), c2addr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if n != 4 {
+		t.Fatalf("got %d; want 4", n)
+	}
+}