net/http: update bundled http2, add h2 Transport.IdleConnTimeout tests

Updates bundled http2 to x/net git rev a333c53 for:

   http2: add Transport support for IdleConnTimeout
   https://golang.org/cl/30075

And add tests.

The bundled http2 also includes a change adding a Ping method to
http2.ClientConn, but that type isn't exposed in the standard
library. Nevertheless, the code gets compiled and adds a dependency on
"crypto/rand", requiring an update to go/build's dependency
test. Because net/http already depends on crypto/tls, which uses
crypto/rand, it's not really a new dependency.

Fixes golang#16808

Change-Id: I1ec8666ea74762f27c70a6f30a366a6647f923f7
Reviewed-on: https://go-review.googlesource.com/30078
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Author: bradfitz

src/go/build/deps_test.go

@@ -376,16 +376,21 @@ var pkgDeps = map[string][]string{
 	// HTTP, kingpin of dependencies.
 	"net/http": {
 		"L4", "NET", "OS",
-		"context", "compress/gzip", "container/list", "crypto/tls",
-		"mime/multipart", "runtime/debug",
-		"net/http/internal",
+		"compress/gzip",
+		"container/list",
+		"context",
+		"crypto/rand",
+		"crypto/tls",
 		"golang_org/x/net/http2/hpack",
 		"golang_org/x/net/idna",
 		"golang_org/x/net/lex/httplex",
 		"golang_org/x/text/unicode/norm",
 		"golang_org/x/text/width",
 		"internal/nettrace",
+		"mime/multipart",
 		"net/http/httptrace",
+		"net/http/internal",
+		"runtime/debug",
 	},
 	"net/http/internal":  {"L4"},
 	"net/http/httptrace": {"context", "internal/nettrace", "net", "reflect", "time"},

src/net/http/export_test.go

@@ -100,6 +100,24 @@ func (t *Transport) IdleConnStrsForTesting() []string {
 	return ret
 }
 
+func (t *Transport) IdleConnStrsForTesting_h2() []string {
+	var ret []string
+	noDialPool := t.h2transport.ConnPool.(http2noDialClientConnPool)
+	pool := noDialPool.http2clientConnPool
+
+	pool.mu.Lock()
+	defer pool.mu.Unlock()
+
+	for k, cc := range pool.conns {
+		for range cc {
+			ret = append(ret, k)
+		}
+	}
+
+	sort.Strings(ret)
+	return ret
+}
+
 func (t *Transport) IdleConnCountForTesting(cacheKey string) int {
 	t.idleMu.Lock()
 	defer t.idleMu.Unlock()

src/net/http/h2_bundle.go

@@ -3481,27 +3481,36 @@ func TestTransportMaxIdleConns(t *testing.T) {
 	}
 }
 
-func TestTransportIdleConnTimeout(t *testing.T) {
+func TestTransportIdleConnTimeout_h1(t *testing.T) { testTransportIdleConnTimeout(t, h1Mode) }
+func TestTransportIdleConnTimeout_h2(t *testing.T) { testTransportIdleConnTimeout(t, h2Mode) }
+func testTransportIdleConnTimeout(t *testing.T, h2 bool) {
 	if testing.Short() {
 		t.Skip("skipping in short mode")
 	}
 	defer afterTest(t)
 
-	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
+	const timeout = 1 * time.Second
+
+	cst := newClientServerTest(t, h2, HandlerFunc(func(w ResponseWriter, r *Request) {
 		// No body for convenience.
 	}))
-	defer ts.Close()
-
-	const timeout = 1 * time.Second
-	tr := &Transport{
-		IdleConnTimeout: timeout,
-	}
+	defer cst.close()
+	tr := cst.tr
+	tr.IdleConnTimeout = timeout
 	defer tr.CloseIdleConnections()
 	c := &Client{Transport: tr}
 
+	idleConns := func() []string {
+		if h2 {
+			return tr.IdleConnStrsForTesting_h2()
+		} else {
+			return tr.IdleConnStrsForTesting()
+		}
+	}
+
 	var conn string
 	doReq := func(n int) {
-		req, _ := NewRequest("GET", ts.URL, nil)
+		req, _ := NewRequest("GET", cst.ts.URL, nil)
 		req = req.WithContext(httptrace.WithClientTrace(context.Background(), &httptrace.ClientTrace{
 			PutIdleConn: func(err error) {
 				if err != nil {
@@ -3514,7 +3523,7 @@ func TestTransportIdleConnTimeout(t *testing.T) {
 			t.Fatal(err)
 		}
 		res.Body.Close()
-		conns := tr.IdleConnStrsForTesting()
+		conns := idleConns()
 		if len(conns) != 1 {
 			t.Fatalf("req %v: unexpected number of idle conns: %q", n, conns)
 		}
@@ -3530,7 +3539,7 @@ func TestTransportIdleConnTimeout(t *testing.T) {
 		time.Sleep(timeout / 2)
 	}
 	time.Sleep(timeout * 3 / 2)
-	if got := tr.IdleConnStrsForTesting(); len(got) != 0 {
+	if got := idleConns(); len(got) != 0 {
 		t.Errorf("idle conns = %q; want none", got)
 	}
 }