.

go/internal/xtracing/tracetest/tracetest.go

@@ -490,13 +490,21 @@ type Streams interface {
 type T struct {
 	testing.TB
 
-	streamTabMu sync.Mutex
+	mu         sync.Mutex
 	streamTab  map[/*stream*/string]Chan // set to nil on test shutdown
 	routeEvent func(event interface{}) (stream string)
+	tracev     []eventTrace // record of events as they happen
 
 	nakq []nak // naks queued to be sent after Fatal
 }
 
+// eventTrace keeps information about one event T received via RxEvent.
+type eventTrace struct {
+	t      time.Time   // monotonic
+	stream string
+	event  interface{}
+}
+
 type nak struct {
 	msg *Msg
 	why string
@@ -510,8 +518,8 @@ func (t *T) queuenak(msg *Msg, why string) {
 
 // XXX doc; naming
 func (t *T) SetEventRouter(routeEvent func(event interface{}) (stream string)) {
-	t.streamTabMu.Lock()
-	defer t.streamTabMu.Unlock()
+	t.mu.Lock()
+	defer t.mu.Unlock()
 
 	if t.routeEvent != nil {
 		panic("double call to SetEventRouter")
@@ -521,13 +529,15 @@ func (t *T) SetEventRouter(routeEvent func(event interface{}) (stream string)) {
 
 // XXX doc; naming
 func (t *T) RxEvent(event interface{}) {
+	t0 := time.Now()
 	stream := "default"
-	t.streamTabMu.Lock()
+	t.mu.Lock()
 	if t.routeEvent != nil {
 		stream = t.routeEvent(event)
 	}
+	t.tracev = append(t.tracev, eventTrace{t0, stream, event})
 	ch := t.chanForStream(stream)
-	t.streamTabMu.Unlock()
+	t.mu.Unlock()
 
 	if ch == nil {
 		t.fatalfInNonMain("%s: (pre)send: canceled (test failed)", stream)
@@ -566,7 +576,7 @@ func (t *T) RxEvent(event interface{}) {
 }
 
 // chanForStream returns channel corresponding to stream.
-// must be called under streamTabMu.
+// must be called under mu.
 func (t *T) chanForStream(stream string) Chan {
 	if t.streamTab == nil {
 		return nil // t is no longer operational after e.g. deadlock
@@ -623,9 +633,9 @@ func (t *T) expect1(stream string, eventExpect interface{}) *Msg {
 func (t *T) xget1(stream string, eventp interface{}) *Msg {
 	t.Helper()
 
-	t.streamTabMu.Lock()
+	t.mu.Lock()
 	ch := t.chanForStream(stream)
-	t.streamTabMu.Unlock()
+	t.mu.Unlock()
 
 	// XXX ch == nil -> no longer operational
 
@@ -694,10 +704,10 @@ func (t *T) closeStreamTab() (nnak int) {
 	t.Helper()
 
 	// mark streamTab no longer operational
-	t.streamTabMu.Lock()
+	t.mu.Lock()
 	streamTab := t.streamTab
 	t.streamTab = nil
-	t.streamTabMu.Unlock()
+	t.mu.Unlock()
 
 	if streamTab == nil {
 		return // already closed