net/http: deflake tests in full mode after t.Parallel additions

https://golang.org/cl/18087 added a bunch of t.Parallel calls, which
aren't compatible with the afterTest func. But in short mode, afterTest
is a no-op. To keep all.bash (short mode) fast, conditionally set
t.Parallel when in short mode, but keep it unset for compatibility with
afterFunc otherwise.

Fixes #13804

Change-Id: Ie841fbc2544e1ffbee43ba1afbe895774e290da0
Reviewed-on: https://go-review.googlesource.com/18143Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/net/http/main_test.go

@@ -79,6 +79,15 @@ func goroutineLeaked() bool {
 	return true
 }
 
+// setParallel marks t as a parallel test if we're in short mode
+// (all.bash), but as a serial test otherwise. Using t.Parallel isn't
+// compatible with the afterTest func in non-short mode.
+func setParallel(t *testing.T) {
+	if testing.Short() {
+		t.Parallel()
+	}
+}
+
 func afterTest(t testing.TB) {
 	http.DefaultTransport.(*http.Transport).CloseIdleConnections()
 	if testing.Short() {

src/net/http/serve_test.go

@@ -455,7 +455,7 @@ func TestServerTimeouts(t *testing.T) {
 	if runtime.GOOS == "plan9" {
 		t.Skip("skipping test; see https://golang.org/issue/7237")
 	}
-	t.Parallel()
+	setParallel(t)
 	defer afterTest(t)
 	reqNum := 0
 	ts := httptest.NewUnstartedServer(HandlerFunc(func(res ResponseWriter, req *Request) {
@@ -939,7 +939,7 @@ func TestTLSHandshakeTimeout(t *testing.T) {
 	if runtime.GOOS == "plan9" {
 		t.Skip("skipping test; see https://golang.org/issue/7237")
 	}
-	t.Parallel()
+	setParallel(t)
 	defer afterTest(t)
 	ts := httptest.NewUnstartedServer(HandlerFunc(func(w ResponseWriter, r *Request) {}))
 	errc := make(chanWriter, 10) // but only expecting 1

src/net/http/transport_test.go

@@ -436,7 +436,7 @@ func TestTransportMaxPerHostIdleConns(t *testing.T) {
 }
 
 func TestTransportServerClosingUnexpectedly(t *testing.T) {
-	t.Parallel()
+	setParallel(t)
 	defer afterTest(t)
 	ts := httptest.NewServer(hostPortHandler)
 	defer ts.Close()
@@ -969,7 +969,7 @@ func TestTransportGzipShort(t *testing.T) {
 
 // tests that persistent goroutine connections shut down when no longer desired.
 func TestTransportPersistConnLeak(t *testing.T) {
-	t.Parallel()
+	setParallel(t)
 	defer afterTest(t)
 	gotReqCh := make(chan bool)
 	unblockCh := make(chan bool)
@@ -1036,7 +1036,7 @@ func TestTransportPersistConnLeak(t *testing.T) {
 // golang.org/issue/4531: Transport leaks goroutines when
 // request.ContentLength is explicitly short
 func TestTransportPersistConnLeakShortBody(t *testing.T) {
-	t.Parallel()
+	setParallel(t)
 	defer afterTest(t)
 	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
 	}))
@@ -1377,7 +1377,7 @@ func TestIssue4191_InfiniteGetToPutTimeout(t *testing.T) {
 }
 
 func TestTransportResponseHeaderTimeout(t *testing.T) {
-	t.Parallel()
+	setParallel(t)
 	defer afterTest(t)
 	if testing.Short() {
 		t.Skip("skipping timeout test in -short mode")
@@ -1449,7 +1449,7 @@ func TestTransportResponseHeaderTimeout(t *testing.T) {
 }
 
 func TestTransportCancelRequest(t *testing.T) {
-	t.Parallel()
+	setParallel(t)
 	defer afterTest(t)
 	if testing.Short() {
 		t.Skip("skipping test in -short mode")
@@ -1559,7 +1559,7 @@ Get = Get http://something.no-network.tld/: net/http: request canceled while wai
 }
 
 func TestCancelRequestWithChannel(t *testing.T) {
-	t.Parallel()
+	setParallel(t)
 	defer afterTest(t)
 	if testing.Short() {
 		t.Skip("skipping test in -short mode")
@@ -1617,7 +1617,7 @@ func TestCancelRequestWithChannel(t *testing.T) {
 }
 
 func TestCancelRequestWithChannelBeforeDo(t *testing.T) {
-	t.Parallel()
+	setParallel(t)
 	defer afterTest(t)
 	unblockc := make(chan bool)
 	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
@@ -2495,7 +2495,7 @@ func TestRetryIdempotentRequestsOnError(t *testing.T) {
 
 // Issue 6981
 func TestTransportClosesBodyOnError(t *testing.T) {
-	t.Parallel()
+	setParallel(t)
 	defer afterTest(t)
 	readBody := make(chan error, 1)
 	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {