net/http: use synctest.Test rather than Run

Use the non-experimental Test function.
As a bonus, this lets us drop the hacks we were doing to support
t.Cleanup inside bubbles.

Change-Id: I070624e1384494e9d5fcfee594cfbb7680c1beda
Reviewed-on: https://go-review.googlesource.com/c/go/+/675315
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Damien Neil <dneil@google.com>
Reviewed-by: Jonathan Amsterdam <jba@google.com>

src/net/http/clientserver_test.go

@@ -15,7 +15,6 @@ import (
 	"crypto/tls"
 	"fmt"
 	"hash"
-	"internal/synctest"
 	"io"
 	"log"
 	"maps"
@@ -34,6 +33,7 @@ import (
 	"sync"
 	"sync/atomic"
 	"testing"
+	"testing/synctest"
 	"time"
 )
 
@@ -95,33 +95,13 @@ func run[T TBRun[T]](t T, f func(t T, mode testMode), opts ...any) {
 	}
 }
 
-// cleanupT wraps a testing.T and adds its own Cleanup method.
-// Used to execute cleanup functions within a synctest bubble.
-type cleanupT struct {
-	*testing.T
-	cleanups []func()
-}
-
-// Cleanup replaces T.Cleanup.
-func (t *cleanupT) Cleanup(f func()) {
-	t.cleanups = append(t.cleanups, f)
-}
-
-func (t *cleanupT) done() {
-	for _, f := range slices.Backward(t.cleanups) {
-		f()
-	}
-}
-
 // runSynctest is run combined with synctest.Run.
 //
 // The TB passed to f arranges for cleanup functions to be run in the synctest bubble.
-func runSynctest(t *testing.T, f func(t testing.TB, mode testMode), opts ...any) {
+func runSynctest(t *testing.T, f func(t *testing.T, mode testMode), opts ...any) {
 	run(t, func(t *testing.T, mode testMode) {
-		synctest.Run(func() {
-			ct := &cleanupT{T: t}
-			defer ct.done()
-			f(ct, mode)
+		synctest.Test(t, func(t *testing.T) {
+			f(t, mode)
 		})
 	}, opts...)
 }
@@ -292,12 +272,12 @@ func TestNewClientServerTest(t *testing.T) {
 		}, modes)
 	})
 	t.Run("synctest", func(t *testing.T) {
-		runSynctest(t, func(t testing.TB, mode testMode) {
+		runSynctest(t, func(t *testing.T, mode testMode) {
 			testNewClientServerTest(t, mode, optFakeNet)
 		}, modes)
 	})
 }
-func testNewClientServerTest(t testing.TB, mode testMode, opts ...any) {
+func testNewClientServerTest(t *testing.T, mode testMode, opts ...any) {
 	var got struct {
 		sync.Mutex
 		proto  string

src/net/http/serve_test.go

@@ -5855,7 +5855,7 @@ func testServerShutdown(t *testing.T, mode testMode) {
 }
 
 func TestServerShutdownStateNew(t *testing.T) { runSynctest(t, testServerShutdownStateNew) }
-func testServerShutdownStateNew(t testing.TB, mode testMode) {
+func testServerShutdownStateNew(t *testing.T, mode testMode) {
 	if testing.Short() {
 		t.Skip("test takes 5-6 seconds; skipping in short mode")
 	}

src/net/http/transport_test.go

@@ -4230,7 +4230,7 @@ func TestTransportIdleConnRacesRequest(t *testing.T) {
 	// block the connection closing.
 	runSynctest(t, testTransportIdleConnRacesRequest, []testMode{http1Mode, http2UnencryptedMode})
 }
-func testTransportIdleConnRacesRequest(t testing.TB, mode testMode) {
+func testTransportIdleConnRacesRequest(t *testing.T, mode testMode) {
 	if mode == http2UnencryptedMode {
 		t.Skip("remove skip when #70515 is fixed")
 	}
@@ -4305,7 +4305,7 @@ func testTransportIdleConnRacesRequest(t testing.TB, mode testMode) {
 func TestTransportRemovesConnsAfterIdle(t *testing.T) {
 	runSynctest(t, testTransportRemovesConnsAfterIdle)
 }
-func testTransportRemovesConnsAfterIdle(t testing.TB, mode testMode) {
+func testTransportRemovesConnsAfterIdle(t *testing.T, mode testMode) {
 	if testing.Short() {
 		t.Skip("skipping in short mode")
 	}
@@ -4351,7 +4351,7 @@ func testTransportRemovesConnsAfterIdle(t testing.TB, mode testMode) {
 func TestTransportRemovesConnsAfterBroken(t *testing.T) {
 	runSynctest(t, testTransportRemovesConnsAfterBroken)
 }
-func testTransportRemovesConnsAfterBroken(t testing.TB, mode testMode) {
+func testTransportRemovesConnsAfterBroken(t *testing.T, mode testMode) {
 	if testing.Short() {
 		t.Skip("skipping in short mode")
 	}