dhcp4: only run the linuxConn tests on linux.

Seems obvious when you say it like that! Fixes #41.

dhcp4/conn_linux_test.go

@@ -0,0 +1,46 @@
+// Copyright 2016 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//+build linux
+
+package dhcp4
+
+import (
+	"net"
+	"os"
+	"runtime"
+	"testing"
+)
+
+func TestLinuxConn(t *testing.T) {
+	if runtime.GOOS != "linux" {
+		t.Skipf("not supported on %s", runtime.GOOS)
+	}
+	if os.Getuid() != 0 {
+		t.Skipf("must be root on %s", runtime.GOOS)
+	}
+
+	// Use a listener to grab a free port, but we don't use it beyond
+	// that.
+	l, err := net.ListenPacket("udp4", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	c, err := newLinuxConn(l.LocalAddr().(*net.UDPAddr).Port)
+	if err != nil {
+		t.Fatalf("creating the linuxconn: %s", err)
+	}
+
+	testConn(t, c, l.LocalAddr().String())
+}

dhcp4/conn_test.go

@@ -16,9 +16,7 @@ package dhcp4
 
 import (
 	"net"
-	"os"
 	"reflect"
-	"runtime"
 	"testing"
 	"time"
 )
@@ -132,25 +130,3 @@ func TestPortableConn(t *testing.T) {
 
 	testConn(t, c, addr)
 }
-
-func TestLinuxConn(t *testing.T) {
-	if runtime.GOOS != "linux" {
-		t.Skipf("not supported on %s", runtime.GOOS)
-	}
-	if os.Getuid() != 0 {
-		t.Skipf("must be root on %s", runtime.GOOS)
-	}
-
-	// Use a listener to grab a free port, but we don't use it beyond
-	// that.
-	l, err := net.ListenPacket("udp4", "127.0.0.1:0")
-	if err != nil {
-		t.Fatal(err)
-	}
-	c, err := newLinuxConn(l.LocalAddr().(*net.UDPAddr).Port)
-	if err != nil {
-		t.Fatalf("creating the linuxconn: %s", err)
-	}
-
-	testConn(t, c, l.LocalAddr().String())
-}