http2: deflake TestTransportMaxFrameReadSize

Rewrite this test to examine the SETTINGS frame sent by the Transport
directly, rather than poking around in the Server internals to find
the sent value.

Fixes golang/go#56806

Change-Id: I47859352a14b7120ef88fce5bd000716b9abdad7
Reviewed-on: https://go-review.googlesource.com/c/net/+/451775
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Damien Neil <dneil@google.com>
Auto-Submit: Damien Neil <dneil@google.com>

http2/transport_test.go

@@ -741,12 +741,13 @@ func (fw flushWriter) Write(p []byte) (n int, err error) {
 }
 
 type clientTester struct {
- t *testing.T
- tr *Transport
- sc, cc net.Conn // server and client conn
- fr *Framer // server's framer
- client func() error
- server func() error
+ t *testing.T
+ tr *Transport
+ sc, cc net.Conn // server and client conn
+ fr *Framer // server's framer
+ settings *SettingsFrame
+ client func() error
+ server func() error
 }
 
 func newClientTester(t *testing.T) *clientTester {
@@ -809,9 +810,9 @@ func (ct *clientTester) greet(settings ...Setting) {
  if err != nil {
  ct.t.Fatalf("Reading client settings frame: %v", err)
  }
- if sf, ok := f.(*SettingsFrame); !ok {
+ var ok bool
+ if ct.settings, ok = f.(*SettingsFrame); !ok {
  ct.t.Fatalf("Wanted client settings frame; got %v", f)
- _ = sf // stash it away?
  }
  if err := ct.fr.WriteSettings(settings...); err != nil {
  ct.t.Fatal(err)
@@ -3998,62 +3999,42 @@ func TestTransportResponseDataBeforeHeaders(t *testing.T) {
  ct.run()
 }
 
-// Test that the server received values are in range.
 func TestTransportMaxFrameReadSize(t *testing.T) {
- st := newServerTester(t, func(w http.ResponseWriter, r *http.Request) {
- }, func(s *Server) {
- s.MaxConcurrentStreams = 1
- })
- defer st.Close()
- tr := &Transport{
- TLSClientConfig: tlsConfigInsecure,
- MaxReadFrameSize: 64000,
- }
- defer tr.CloseIdleConnections()
-
- req, err := http.NewRequest("GET", st.ts.URL, nil)
- if err != nil {
- t.Fatal(err)
- }
- res, err := tr.RoundTrip(req)
- if err != nil {
- t.Fatal(err)
- }
- if got, want := res.StatusCode, 200; got != want {
- t.Errorf("StatusCode = %v; want %v", got, want)
- }
- if res != nil && res.Body != nil {
- res.Body.Close()
- }
- // Test that maxFrameReadSize() matches the requested size.
- if got, want := tr.maxFrameReadSize(), uint32(64000); got != want {
- t.Errorf("maxFrameReadSize = %v; want %v", got, want)
- }
- // Test that server receives the requested size.
- if got, want := st.sc.maxFrameSize, int32(64000); got != want {
- t.Errorf("maxFrameReadSize = %v; want %v", got, want)
- }
-
- // test for minimum frame read size
- tr = &Transport{
- TLSClientConfig: tlsConfigInsecure,
- MaxReadFrameSize: 1024,
- }
-
- if got, want := tr.maxFrameReadSize(), uint32(minMaxFrameSize); got != want {
- t.Errorf("maxFrameReadSize = %v; want %v", got, want)
- }
-
- // test for maximum frame size
- tr = &Transport{
- TLSClientConfig: tlsConfigInsecure,
- MaxReadFrameSize: 1024 * 1024 * 16,
- }
-
- if got, want := tr.maxFrameReadSize(), uint32(maxFrameSize); got != want {
- t.Errorf("maxFrameReadSize = %v; want %v", got, want)
+ for _, test := range []struct {
+ maxReadFrameSize uint32
+ want uint32
+ }{{
+ maxReadFrameSize: 64000,
+ want: 64000,
+ }, {
+ maxReadFrameSize: 1024,
+ want: minMaxFrameSize,
+ }} {
+ ct := newClientTester(t)
+ ct.tr.MaxReadFrameSize = test.maxReadFrameSize
+ ct.client = func() error {
+ req, _ := http.NewRequest("GET", "https://dummy.tld/", http.NoBody)
+ ct.tr.RoundTrip(req)
+ return nil
+ }
+ ct.server = func() error {
+ defer ct.cc.(*net.TCPConn).Close()
+ ct.greet()
+ var got uint32
+ ct.settings.ForeachSetting(func(s Setting) error {
+ switch s.ID {
+ case SettingMaxFrameSize:
+ got = s.Val
+ }
+ return nil
+ })
+ if got != test.want {
+ t.Errorf("Transport.MaxReadFrameSize = %v; server got %v, want %v", test.maxReadFrameSize, got, test.want)
+ }
+ return nil
+ }
+ ct.run()
  }
-
 }
 
 func TestTransportRequestsLowServerLimit(t *testing.T) {