http2: use synthetic time in server tests

Change newServerTester to return a server using fake time
and a fake net.Conn.

Change-Id: I9d5db0cbe75696aed6d99ff1cd2369c2dea426c3
Reviewed-on: https://go-review.googlesource.com/c/net/+/586247
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Jonathan Amsterdam <jba@google.com>

http2/http2.go

@@ -17,6 +17,7 @@ package http2 // import "golang.org/x/net/http2"
 
 import (
 	"bufio"
+	"context"
 	"crypto/tls"
 	"fmt"
 	"io"
@@ -26,6 +27,7 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+	"time"
 
 	"golang.org/x/net/http/httpguts"
 )
@@ -377,3 +379,14 @@ func validPseudoPath(v string) bool {
 // makes that struct also non-comparable, and generally doesn't add
 // any size (as long as it's first).
 type incomparable [0]func()
+
+// synctestGroupInterface is the methods of synctestGroup used by Server and Transport.
+// It's defined as an interface here to let us keep synctestGroup entirely test-only
+// and not a part of non-test builds.
+type synctestGroupInterface interface {
+	Join()
+	Now() time.Time
+	NewTimer(d time.Duration) timer
+	AfterFunc(d time.Duration, f func()) timer
+	ContextWithTimeout(ctx context.Context, d time.Duration) (context.Context, context.CancelFunc)
+}

http2/server.go

@@ -154,6 +154,39 @@ type Server struct {
 	// so that we don't embed a Mutex in this struct, which will make the
 	// struct non-copyable, which might break some callers.
 	state *serverInternalState
+
+	// Synchronization group used for testing.
+	// Outside of tests, this is nil.
+	group synctestGroupInterface
+}
+
+func (s *Server) markNewGoroutine() {
+	if s.group != nil {
+		s.group.Join()
+	}
+}
+
+func (s *Server) now() time.Time {
+	if s.group != nil {
+		return s.group.Now()
+	}
+	return time.Now()
+}
+
+// newTimer creates a new time.Timer, or a synthetic timer in tests.
+func (s *Server) newTimer(d time.Duration) timer {
+	if s.group != nil {
+		return s.group.NewTimer(d)
+	}
+	return timeTimer{time.NewTimer(d)}
+}
+
+// afterFunc creates a new time.AfterFunc timer, or a synthetic timer in tests.
+func (s *Server) afterFunc(d time.Duration, f func()) timer {
+	if s.group != nil {
+		return s.group.AfterFunc(d, f)
+	}
+	return timeTimer{time.AfterFunc(d, f)}
 }
 
 func (s *Server) initialConnRecvWindowSize() int32 {
@@ -400,6 +433,10 @@ func (o *ServeConnOpts) handler() http.Handler {
 //
 // The opts parameter is optional. If nil, default values are used.
 func (s *Server) ServeConn(c net.Conn, opts *ServeConnOpts) {
+	s.serveConn(c, opts, nil)
+}
+
+func (s *Server) serveConn(c net.Conn, opts *ServeConnOpts, newf func(*serverConn)) {
 	baseCtx, cancel := serverConnBaseContext(c, opts)
 	defer cancel()
 
@@ -426,6 +463,9 @@ func (s *Server) ServeConn(c net.Conn, opts *ServeConnOpts) {
 		pushEnabled:                 true,
 		sawClientPreface:            opts.SawClientPreface,
 	}
+	if newf != nil {
+		newf(sc)
+	}
 
 	s.state.registerConn(sc)
 	defer s.state.unregisterConn(sc)
@@ -599,8 +639,8 @@ type serverConn struct {
 	inFrameScheduleLoop         bool              // whether we're in the scheduleFrameWrite loop
 	needToSendGoAway            bool              // we need to schedule a GOAWAY frame write
 	goAwayCode                  ErrCode
-	shutdownTimer               *time.Timer // nil until used
-	idleTimer                   *time.Timer // nil if unused
+	shutdownTimer               timer // nil until used
+	idleTimer                   timer // nil if unused
 
 	// Owned by the writeFrameAsync goroutine:
 	headerWriteBuf bytes.Buffer
@@ -649,12 +689,12 @@ type stream struct {
 	flow             outflow // limits writing from Handler to client
 	inflow           inflow  // what the client is allowed to POST/etc to us
 	state            streamState
-	resetQueued      bool        // RST_STREAM queued for write; set by sc.resetStream
-	gotTrailerHeader bool        // HEADER frame for trailers was seen
-	wroteHeaders     bool        // whether we wrote headers (not status 100)
-	readDeadline     *time.Timer // nil if unused
-	writeDeadline    *time.Timer // nil if unused
-	closeErr         error       // set before cw is closed
+	resetQueued      bool  // RST_STREAM queued for write; set by sc.resetStream
+	gotTrailerHeader bool  // HEADER frame for trailers was seen
+	wroteHeaders     bool  // whether we wrote headers (not status 100)
+	readDeadline     timer // nil if unused
+	writeDeadline    timer // nil if unused
+	closeErr         error // set before cw is closed
 
 	trailer    http.Header // accumulated trailers
 	reqTrailer http.Header // handler's Request.Trailer
@@ -811,6 +851,7 @@ type readFrameResult struct {
 // consumer is done with the frame.
 // It's run on its own goroutine.
 func (sc *serverConn) readFrames() {
+	sc.srv.markNewGoroutine()
 	gate := make(chan struct{})
 	gateDone := func() { gate <- struct{}{} }
 	for {
@@ -843,6 +884,7 @@ type frameWriteResult struct {
 // At most one goroutine can be running writeFrameAsync at a time per
 // serverConn.
 func (sc *serverConn) writeFrameAsync(wr FrameWriteRequest, wd *writeData) {
+	sc.srv.markNewGoroutine()
 	var err error
 	if wd == nil {
 		err = wr.write.writeFrame(sc)
@@ -922,13 +964,13 @@ func (sc *serverConn) serve() {
 	sc.setConnState(http.StateIdle)
 
 	if sc.srv.IdleTimeout > 0 {
-		sc.idleTimer = time.AfterFunc(sc.srv.IdleTimeout, sc.onIdleTimer)
+		sc.idleTimer = sc.srv.afterFunc(sc.srv.IdleTimeout, sc.onIdleTimer)
 		defer sc.idleTimer.Stop()
 	}
 
 	go sc.readFrames() // closed by defer sc.conn.Close above
 
-	settingsTimer := time.AfterFunc(firstSettingsTimeout, sc.onSettingsTimer)
+	settingsTimer := sc.srv.afterFunc(firstSettingsTimeout, sc.onSettingsTimer)
 	defer settingsTimer.Stop()
 
 	loopNum := 0
@@ -1057,10 +1099,10 @@ func (sc *serverConn) readPreface() error {
 			errc <- nil
 		}
 	}()
-	timer := time.NewTimer(prefaceTimeout) // TODO: configurable on *Server?
+	timer := sc.srv.newTimer(prefaceTimeout) // TODO: configurable on *Server?
 	defer timer.Stop()
 	select {
-	case <-timer.C:
+	case <-timer.C():
 		return errPrefaceTimeout
 	case err := <-errc:
 		if err == nil {
@@ -1425,7 +1467,7 @@ func (sc *serverConn) goAway(code ErrCode) {
 
 func (sc *serverConn) shutDownIn(d time.Duration) {
 	sc.serveG.check()
-	sc.shutdownTimer = time.AfterFunc(d, sc.onShutdownTimer)
+	sc.shutdownTimer = sc.srv.afterFunc(d, sc.onShutdownTimer)
 }
 
 func (sc *serverConn) resetStream(se StreamError) {
@@ -2022,7 +2064,7 @@ func (sc *serverConn) processHeaders(f *MetaHeadersFrame) error {
 	// (in Go 1.8), though. That's a more sane option anyway.
 	if sc.hs.ReadTimeout > 0 {
 		sc.conn.SetReadDeadline(time.Time{})
-		st.readDeadline = time.AfterFunc(sc.hs.ReadTimeout, st.onReadTimeout)
+		st.readDeadline = sc.srv.afterFunc(sc.hs.ReadTimeout, st.onReadTimeout)
 	}
 
 	return sc.scheduleHandler(id, rw, req, handler)
@@ -2120,7 +2162,7 @@ func (sc *serverConn) newStream(id, pusherID uint32, state streamState) *stream
 	st.flow.add(sc.initialStreamSendWindowSize)
 	st.inflow.init(sc.srv.initialStreamRecvWindowSize())
 	if sc.hs.WriteTimeout > 0 {
-		st.writeDeadline = time.AfterFunc(sc.hs.WriteTimeout, st.onWriteTimeout)
+		st.writeDeadline = sc.srv.afterFunc(sc.hs.WriteTimeout, st.onWriteTimeout)
 	}
 
 	sc.streams[id] = st
@@ -2344,6 +2386,7 @@ func (sc *serverConn) handlerDone() {
 
 // Run on its own goroutine.
 func (sc *serverConn) runHandler(rw *responseWriter, req *http.Request, handler func(http.ResponseWriter, *http.Request)) {
+	sc.srv.markNewGoroutine()
 	defer sc.sendServeMsg(handlerDoneMsg)
 	didPanic := true
 	defer func() {
@@ -2640,7 +2683,7 @@ func (rws *responseWriterState) writeChunk(p []byte) (n int, err error) {
 		var date string
 		if _, ok := rws.snapHeader["Date"]; !ok {
 			// TODO(bradfitz): be faster here, like net/http? measure.
-			date = time.Now().UTC().Format(http.TimeFormat)
+			date = rws.conn.srv.now().UTC().Format(http.TimeFormat)
 		}
 
 		for _, v := range rws.snapHeader["Trailer"] {
@@ -2762,7 +2805,7 @@ func (rws *responseWriterState) promoteUndeclaredTrailers() {
 
 func (w *responseWriter) SetReadDeadline(deadline time.Time) error {
 	st := w.rws.stream
-	if !deadline.IsZero() && deadline.Before(time.Now()) {
+	if !deadline.IsZero() && deadline.Before(w.rws.conn.srv.now()) {
 		// If we're setting a deadline in the past, reset the stream immediately
 		// so writes after SetWriteDeadline returns will fail.
 		st.onReadTimeout()
@@ -2778,17 +2821,17 @@ func (w *responseWriter) SetReadDeadline(deadline time.Time) error {
 		if deadline.IsZero() {
 			st.readDeadline = nil
 		} else if st.readDeadline == nil {
-			st.readDeadline = time.AfterFunc(deadline.Sub(time.Now()), st.onReadTimeout)
+			st.readDeadline = sc.srv.afterFunc(deadline.Sub(w.rws.conn.srv.now()), st.onReadTimeout)
 		} else {
-			st.readDeadline.Reset(deadline.Sub(time.Now()))
+			st.readDeadline.Reset(deadline.Sub(w.rws.conn.srv.now()))
 		}
 	})
 	return nil
 }
 
 func (w *responseWriter) SetWriteDeadline(deadline time.Time) error {
 	st := w.rws.stream
-	if !deadline.IsZero() && deadline.Before(time.Now()) {
+	if !deadline.IsZero() && deadline.Before(w.rws.conn.srv.now()) {
 		// If we're setting a deadline in the past, reset the stream immediately
 		// so writes after SetWriteDeadline returns will fail.
 		st.onWriteTimeout()
@@ -2804,9 +2847,9 @@ func (w *responseWriter) SetWriteDeadline(deadline time.Time) error {
 		if deadline.IsZero() {
 			st.writeDeadline = nil
 		} else if st.writeDeadline == nil {
-			st.writeDeadline = time.AfterFunc(deadline.Sub(time.Now()), st.onWriteTimeout)
+			st.writeDeadline = sc.srv.afterFunc(deadline.Sub(w.rws.conn.srv.now()), st.onWriteTimeout)
 		} else {
-			st.writeDeadline.Reset(deadline.Sub(time.Now()))
+			st.writeDeadline.Reset(deadline.Sub(w.rws.conn.srv.now()))
 		}
 	})
 	return nil

http2/server_push_test.go

@@ -105,7 +105,7 @@ func TestServer_Push_Success(t *testing.T) {
 			errc <- fmt.Errorf("unknown RequestURL %q", r.URL.RequestURI())
 		}
 	})
-	stURL = st.ts.URL
+	stURL = "https://" + st.authority()
 
 	// Send one request, which should push two responses.
 	st.greet()
@@ -169,7 +169,7 @@ func TestServer_Push_Success(t *testing.T) {
 				return checkPushPromise(f, 2, [][2]string{
 					{":method", "GET"},
 					{":scheme", "https"},
-					{":authority", st.ts.Listener.Addr().String()},
+					{":authority", st.authority()},
 					{":path", "/pushed?get"},
 					{"user-agent", userAgent},
 				})
@@ -178,7 +178,7 @@ func TestServer_Push_Success(t *testing.T) {
 				return checkPushPromise(f, 4, [][2]string{
 					{":method", "HEAD"},
 					{":scheme", "https"},
-					{":authority", st.ts.Listener.Addr().String()},
+					{":authority", st.authority()},
 					{":path", "/pushed?head"},
 					{"cookie", cookie},
 					{"user-agent", userAgent},