http2: workaround TCPConn CloseWrite not being supported on Plan 9

This stops the tests from hanging on Plan 9.

Fixes golang/go#35904
Updates golang/go#17906

Change-Id: I2bcbb131629b217a99f9496cda0399ce21eb3020
Reviewed-on: https://go-review.googlesource.com/c/net/+/209417
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

http2/transport_test.go

@@ -832,6 +832,10 @@ func testTransportReqBodyAfterResponse(t *testing.T, status int) {
 	ct := newClientTester(t)
 	ct.client = func() error {
 		defer ct.cc.(*net.TCPConn).CloseWrite()
+		if runtime.GOOS == "plan9" {
+			// CloseWrite not supported on Plan 9; Issue 17906
+			defer ct.cc.(*net.TCPConn).Close()
+		}
 		defer close(clientDone)
 
 		var n int64 // atomic
@@ -2693,6 +2697,10 @@ func testTransportUsesGoAwayDebugError(t *testing.T, failMidBody bool) {
 			ct.fr.WriteGoAway(5, ErrCodeNo, []byte(goAwayDebugData))
 			ct.fr.WriteGoAway(5, goAwayErrCode, nil)
 			ct.sc.(*net.TCPConn).CloseWrite()
+			if runtime.GOOS == "plan9" {
+				// CloseWrite not supported on Plan 9; Issue 17906
+				ct.sc.(*net.TCPConn).Close()
+			}
 			<-clientDone
 			return nil
 		}
@@ -2821,6 +2829,10 @@ func TestTransportAdjustsFlowControl(t *testing.T) {
 
 	ct.client = func() error {
 		defer ct.cc.(*net.TCPConn).CloseWrite()
+		if runtime.GOOS == "plan9" {
+			// CloseWrite not supported on Plan 9; Issue 17906
+			defer ct.cc.(*net.TCPConn).Close()
+		}
 		defer close(clientDone)
 
 		req, _ := http.NewRequest("POST", "https://dummy.tld/", struct{ io.Reader }{io.LimitReader(neverEnding('A'), bodySize)})
@@ -3449,6 +3461,10 @@ func TestTransportRetryAfterRefusedStream(t *testing.T) {
 	ct := newClientTester(t)
 	ct.client = func() error {
 		defer ct.cc.(*net.TCPConn).CloseWrite()
+		if runtime.GOOS == "plan9" {
+			// CloseWrite not supported on Plan 9; Issue 17906
+			defer ct.cc.(*net.TCPConn).Close()
+		}
 		defer close(clientDone)
 		req, _ := http.NewRequest("GET", "https://dummy.tld/", nil)
 		resp, err := ct.tr.RoundTrip(req)
@@ -3515,6 +3531,10 @@ func TestTransportRetryHasLimit(t *testing.T) {
 	ct := newClientTester(t)
 	ct.client = func() error {
 		defer ct.cc.(*net.TCPConn).CloseWrite()
+		if runtime.GOOS == "plan9" {
+			// CloseWrite not supported on Plan 9; Issue 17906
+			defer ct.cc.(*net.TCPConn).Close()
+		}
 		defer close(clientDone)
 		req, _ := http.NewRequest("GET", "https://dummy.tld/", nil)
 		resp, err := ct.tr.RoundTrip(req)
@@ -3563,6 +3583,10 @@ func TestTransportResponseDataBeforeHeaders(t *testing.T) {
 	ct := newClientTester(t)
 	ct.client = func() error {
 		defer ct.cc.(*net.TCPConn).CloseWrite()
+		if runtime.GOOS == "plan9" {
+			// CloseWrite not supported on Plan 9; Issue 17906
+			defer ct.cc.(*net.TCPConn).Close()
+		}
 		req := httptest.NewRequest("GET", "https://dummy.tld/", nil)
 		// First request is normal to ensure the check is per stream and not per connection.
 		_, err := ct.tr.RoundTrip(req)
@@ -3675,6 +3699,10 @@ func TestTransportRequestsStallAtServerLimit(t *testing.T) {
 			wg.Wait()
 			close(clientDone)
 			ct.cc.(*net.TCPConn).CloseWrite()
+			if runtime.GOOS == "plan9" {
+				// CloseWrite not supported on Plan 9; Issue 17906
+				ct.cc.(*net.TCPConn).Close()
+			}
 		}()
 		for k := 0; k < maxConcurrent+2; k++ {
 			wg.Add(1)
@@ -4295,6 +4323,10 @@ func testTransportBodyReadError(t *testing.T, body []byte) {
 	ct := newClientTester(t)
 	ct.client = func() error {
 		defer ct.cc.(*net.TCPConn).CloseWrite()
+		if runtime.GOOS == "plan9" {
+			// CloseWrite not supported on Plan 9; Issue 17906
+			defer ct.cc.(*net.TCPConn).Close()
+		}
 		defer close(clientDone)
 
 		checkNoStreams := func() error {
@@ -4383,6 +4415,10 @@ func TestTransportBodyEagerEndStream(t *testing.T) {
 	ct := newClientTester(t)
 	ct.client = func() error {
 		defer ct.cc.(*net.TCPConn).CloseWrite()
+		if runtime.GOOS == "plan9" {
+			// CloseWrite not supported on Plan 9; Issue 17906
+			defer ct.cc.(*net.TCPConn).Close()
+		}
 		body := strings.NewReader(reqBody)
 		req, err := http.NewRequest("PUT", "https://dummy.tld/", body)
 		if err != nil {