control/controlhttp: remove tstest.Clock from tests (#8830)

These specific tests rely on some timers in the controlhttp code.
Without time moving forward and timers triggering, the tests fail.

Updates #8587

Signed-off-by: Andrew Lytvynov <awly@tailscale.com>

control/controlhttp/http_test.go

@@ -26,6 +26,7 @@ import (
 	"tailscale.com/net/tsdial"
 	"tailscale.com/tailcfg"
 	"tailscale.com/tstest"
+	"tailscale.com/tstime"
 	"tailscale.com/types/key"
 	"tailscale.com/types/logger"
 )
@@ -172,8 +173,12 @@ func testControlHTTP(t *testing.T, param httpTestParam) {
 	}
 
 	var httpHandler http.Handler = handler
+	const fallbackDelay = 50 * time.Millisecond
+	clock := tstest.NewClock(tstest.ClockOpts{Step: 2 * fallbackDelay})
+	// Advance once to init the clock.
+	clock.Now()
 	if param.makeHTTPHangAfterUpgrade {
-		httpHandler = http.HandlerFunc(brokenMITMHandler)
+		httpHandler = brokenMITMHandler(clock)
 	}
 	httpServer := &http.Server{Handler: httpHandler}
 	go httpServer.Serve(httpLn)
@@ -204,8 +209,8 @@ func testControlHTTP(t *testing.T, param httpTestParam) {
 		Dialer:               new(tsdial.Dialer).SystemDial,
 		Logf:                 t.Logf,
 		omitCertErrorLogging: true,
-		testFallbackDelay:    50 * time.Millisecond,
-		Clock:                &tstest.Clock{},
+		testFallbackDelay:    fallbackDelay,
+		Clock:                clock,
 	}
 
 	if proxy != nil {
@@ -471,12 +476,16 @@ EKTcWGekdmdDPsHloRNtsiCa697B2O9IFA==
 	}
 }
 
-func brokenMITMHandler(w http.ResponseWriter, r *http.Request) {
-	w.Header().Set("Upgrade", upgradeHeaderValue)
-	w.Header().Set("Connection", "upgrade")
-	w.WriteHeader(http.StatusSwitchingProtocols)
-	w.(http.Flusher).Flush()
-	<-r.Context().Done()
+func brokenMITMHandler(clock tstime.Clock) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Upgrade", upgradeHeaderValue)
+		w.Header().Set("Connection", "upgrade")
+		w.WriteHeader(http.StatusSwitchingProtocols)
+		w.(http.Flusher).Flush()
+		// Advance the clock to trigger HTTPs fallback.
+		clock.Now()
+		<-r.Context().Done()
+	}
 }
 
 func TestDialPlan(t *testing.T) {
@@ -621,12 +630,15 @@ func TestDialPlan(t *testing.T) {
 	}
 	for _, tt := range testCases {
 		t.Run(tt.name, func(t *testing.T) {
+			// TODO(awly): replace this with tstest.NewClock and update the
+			// test to advance the clock correctly.
+			clock := tstime.StdClock{}
 			makeHandler(t, "fallback", fallbackAddr, nil)
 			makeHandler(t, "good", goodAddr, nil)
 			makeHandler(t, "other", otherAddr, nil)
 			makeHandler(t, "other2", other2Addr, nil)
 			makeHandler(t, "broken", brokenAddr, func(h http.Handler) http.Handler {
-				return http.HandlerFunc(brokenMITMHandler)
+				return brokenMITMHandler(clock)
 			})
 
 			dialer := closeTrackDialer{
@@ -662,7 +674,7 @@ func TestDialPlan(t *testing.T) {
 				drainFinished:        drained,
 				omitCertErrorLogging: true,
 				testFallbackDelay:    50 * time.Millisecond,
-				Clock:                &tstest.Clock{},
+				Clock:                clock,
 			}
 
 			conn, err := a.dial(ctx)