net: add skip message to test

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5753048
diff --git a/src/pkg/net/multicast_test.go b/src/pkg/net/multicast_test.go
index 1d760c2..fe5e8de 100644
--- a/src/pkg/net/multicast_test.go
+++ b/src/pkg/net/multicast_test.go
@@ -47,9 +47,11 @@
 func TestMulticastListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "netbsd", "openbsd", "plan9", "windows":
+		t.Logf("skipping test on %q", runtime.GOOS)
 		return
 	case "linux":
 		if runtime.GOARCH == "arm" || runtime.GOARCH == "alpha" {
+			t.Logf("skipping test on %q/%q", runtime.GOOS, runtime.GOARCH)
 			return
 		}
 	}
@@ -86,6 +88,7 @@
 func TestSimpleMulticastListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
+		t.Logf("skipping test on %q", runtime.GOOS)
 		return
 	}
 
diff --git a/src/pkg/net/net_test.go b/src/pkg/net/net_test.go
index f62fc65..d4409cc 100644
--- a/src/pkg/net/net_test.go
+++ b/src/pkg/net/net_test.go
@@ -21,6 +21,7 @@
 
 func TestShutdown(t *testing.T) {
 	if runtime.GOOS == "plan9" {
+		t.Logf("skipping test on %q", runtime.GOOS)
 		return
 	}
 	l, err := Listen("tcp", "127.0.0.1:0")
diff --git a/src/pkg/net/parse_test.go b/src/pkg/net/parse_test.go
index dfbaba4..30fda45 100644
--- a/src/pkg/net/parse_test.go
+++ b/src/pkg/net/parse_test.go
@@ -13,7 +13,9 @@
 
 func TestReadLine(t *testing.T) {
 	// /etc/services file does not exist on windows and Plan 9.
-	if runtime.GOOS == "windows" || runtime.GOOS == "plan9" {
+	switch runtime.GOOS {
+	case "plan9", "windows":
+		t.Logf("skipping test on %q", runtime.GOOS)
 		return
 	}
 	filename := "/etc/services" // a nice big file
diff --git a/src/pkg/net/server_test.go b/src/pkg/net/server_test.go
index 64a9796..d5ea789 100644
--- a/src/pkg/net/server_test.go
+++ b/src/pkg/net/server_test.go
@@ -142,6 +142,7 @@
 
 func TestSeqpacketConnServer(t *testing.T) {
 	if runtime.GOOS != "linux" {
+		t.Logf("skipping test on %q", runtime.GOOS)
 		return
 	}
 
diff --git a/src/pkg/net/timeout_test.go b/src/pkg/net/timeout_test.go
index acae7fa..672fb72 100644
--- a/src/pkg/net/timeout_test.go
+++ b/src/pkg/net/timeout_test.go
@@ -57,7 +57,9 @@
 }
 
 func TestTimeoutUDP(t *testing.T) {
-	if runtime.GOOS == "plan9" {
+	switch runtime.GOOS {
+	case "plan9":
+		t.Logf("skipping test on %q", runtime.GOOS)
 		return
 	}
 
@@ -73,7 +75,9 @@
 }
 
 func TestTimeoutTCP(t *testing.T) {
-	if runtime.GOOS == "plan9" {
+	switch runtime.GOOS {
+	case "plan9":
+		t.Logf("skipping test on %q", runtime.GOOS)
 		return
 	}
 
@@ -88,7 +92,9 @@
 }
 
 func TestDeadlineReset(t *testing.T) {
-	if runtime.GOOS == "plan9" {
+	switch runtime.GOOS {
+	case "plan9":
+		t.Logf("skipping test on %q", runtime.GOOS)
 		return
 	}
 	ln, err := Listen("tcp", "127.0.0.1:0")
diff --git a/src/pkg/net/udp_test.go b/src/pkg/net/udp_test.go
index ea5fad4..f80d3b5 100644
--- a/src/pkg/net/udp_test.go
+++ b/src/pkg/net/udp_test.go
@@ -10,7 +10,9 @@
 )
 
 func TestWriteToUDP(t *testing.T) {
-	if runtime.GOOS == "plan9" {
+	switch runtime.GOOS {
+	case "plan9":
+		t.Logf("skipping test on %q", runtime.GOOS)
 		return
 	}
 
diff --git a/src/pkg/net/unicast_test.go b/src/pkg/net/unicast_test.go
index 4fd5d32..fc60894 100644
--- a/src/pkg/net/unicast_test.go
+++ b/src/pkg/net/unicast_test.go
@@ -45,6 +45,7 @@
 func TestTCPListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9", "windows":
+		t.Logf("skipping test on %q", runtime.GOOS)
 		return
 	}
 
@@ -80,6 +81,7 @@
 func TestUDPListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9", "windows":
+		t.Logf("skipping test on %q", runtime.GOOS)
 		return
 	}
 
@@ -125,6 +127,7 @@
 func TestSimpleTCPListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
+		t.Logf("skipping test on %q", runtime.GOOS)
 		return
 	}
 
@@ -150,6 +153,7 @@
 func TestSimpleUDPListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
+		t.Logf("skipping test on %q", runtime.GOOS)
 		return
 	}
 
@@ -255,6 +259,7 @@
 func TestDualStackTCPListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
+		t.Logf("skipping test on %q", runtime.GOOS)
 		return
 	}
 	if !supportsIPv6 {
@@ -291,6 +296,7 @@
 func TestDualStackUDPListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
+		t.Logf("skipping test on %q", runtime.GOOS)
 		return
 	}
 	if !supportsIPv6 {
@@ -521,6 +527,7 @@
 func TestProhibitionaryDialArgs(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
+		t.Logf("skipping test on %q", runtime.GOOS)
 		return
 	}
 	// This test requires both IPv6 and IPv6 IPv4-mapping functionality.