log/syslog: disable unix/unixgram tests on android

unix/unixgram is not available to standard Android programs.

For golang/go#10807

Change-Id: I6062c3a25cffb86e58cbbd12a07dc90ffbf57185
Reviewed-on: https://go-review.googlesource.com/16114Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/log/syslog/syslog_test.go

@@ -47,6 +47,22 @@ func runPktSyslog(c net.PacketConn, done chan<- string) {
 
 var crashy = false
 
+func testableNetwork(network string) bool {
+	switch network {
+	case "unix", "unixgram":
+		switch runtime.GOOS {
+		case "darwin":
+			switch runtime.GOARCH {
+			case "arm", "arm64":
+				return false
+			}
+		case "android":
+			return false
+		}
+	}
+	return true
+}
+
 func runStreamSyslog(l net.Listener, done chan<- string, wg *sync.WaitGroup) {
 	for {
 		var c net.Conn
@@ -119,12 +135,10 @@ func startServer(n, la string, done chan<- string) (addr string, sock io.Closer,
 
 func TestWithSimulated(t *testing.T) {
 	msg := "Test 123"
-	transport := []string{"unix", "unixgram", "udp", "tcp"}
-
-	if runtime.GOOS == "darwin" {
-		switch runtime.GOARCH {
-		case "arm", "arm64":
-			transport = []string{"udp", "tcp"}
+	var transport []string
+	for _, n := range []string{"unix", "unixgram", "udp", "tcp"} {
+		if testableNetwork(n) {
+			transport = append(transport, n)
 		}
 	}
 
@@ -150,14 +164,11 @@ func TestWithSimulated(t *testing.T) {
 }
 
 func TestFlap(t *testing.T) {
-	if runtime.GOOS == "darwin" {
-		switch runtime.GOARCH {
-		case "arm", "arm64":
-			t.Skipf("skipping on %s/%s", runtime.GOOS, runtime.GOARCH)
-		}
+	net := "unix"
+	if !testableNetwork(net) {
+		t.Skipf("skipping on %s/%s; 'unix' is not supported", runtime.GOOS, runtime.GOARCH)
 	}
 
-	net := "unix"
 	done := make(chan string)
 	addr, sock, srvWG := startServer(net, "", done)
 	defer srvWG.Wait()
@@ -321,10 +332,10 @@ func TestConcurrentReconnect(t *testing.T) {
 	const N = 10
 	const M = 100
 	net := "unix"
-	if runtime.GOOS == "darwin" {
-		switch runtime.GOARCH {
-		case "arm", "arm64":
-			net = "tcp"
+	if !testableNetwork(net) {
+		net = "tcp"
+		if !testableNetwork(net) {
+			t.Skipf("skipping on %s/%s; neither 'unix' or 'tcp' is supported", runtime.GOOS, runtime.GOARCH)
 		}
 	}
 	done := make(chan string, N*M)