diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/recents/RecentsTransitionHandler.java b/libs/WindowManager/Shell/src/com/android/wm/shell/recents/RecentsTransitionHandler.java
index bffc51c..3e568e9 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/recents/RecentsTransitionHandler.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/recents/RecentsTransitionHandler.java
@@ -48,6 +48,7 @@
 import android.window.WindowContainerToken;
 import android.window.WindowContainerTransaction;
 
+import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.protolog.common.ProtoLog;
 import com.android.wm.shell.common.ShellExecutor;
 import com.android.wm.shell.protolog.ShellProtoLogGroup;
@@ -97,7 +98,8 @@
         mMixers.remove(mixer);
     }
 
-    void startRecentsTransition(PendingIntent intent, Intent fillIn, Bundle options,
+    @VisibleForTesting
+    public IBinder startRecentsTransition(PendingIntent intent, Intent fillIn, Bundle options,
             IApplicationThread appThread, IRecentsAnimationRunner listener) {
         ProtoLog.v(ShellProtoLogGroup.WM_SHELL_RECENTS_TRANSITION,
                 "RecentsTransitionHandler.startRecentsTransition");
@@ -121,12 +123,13 @@
         if (mixer != null) {
             mixer.setRecentsTransition(transition);
         }
-        if (transition == null) {
+        if (transition != null) {
+            controller.setTransition(transition);
+            mControllers.add(controller);
+        } else {
             controller.cancel("startRecentsTransition");
-            return;
         }
-        controller.setTransition(transition);
-        mControllers.add(controller);
+        return transition;
     }
 
     @Override
diff --git a/libs/WindowManager/Shell/tests/unittest/Android.bp b/libs/WindowManager/Shell/tests/unittest/Android.bp
index 57a6981..ad4d97f 100644
--- a/libs/WindowManager/Shell/tests/unittest/Android.bp
+++ b/libs/WindowManager/Shell/tests/unittest/Android.bp
@@ -47,7 +47,7 @@
         "truth-prebuilt",
         "testables",
         "platform-test-annotations",
-        "frameworks-base-testutils",
+        "servicestests-utils",
     ],
 
     libs: [
diff --git a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/transition/ShellTransitionTests.java b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/transition/ShellTransitionTests.java
index 8eb5c6a..963632b 100644
--- a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/transition/ShellTransitionTests.java
+++ b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/transition/ShellTransitionTests.java
@@ -17,6 +17,7 @@
 package com.android.wm.shell.transition;
 
 import static android.app.WindowConfiguration.ACTIVITY_TYPE_HOME;
+import static android.app.WindowConfiguration.ACTIVITY_TYPE_RECENTS;
 import static android.app.WindowConfiguration.ACTIVITY_TYPE_STANDARD;
 import static android.app.WindowConfiguration.WINDOWING_MODE_FULLSCREEN;
 import static android.app.WindowConfiguration.WINDOWING_MODE_MULTI_WINDOW;
@@ -50,6 +51,7 @@
 import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.ArgumentMatchers.isNull;
+import static org.mockito.Mockito.after;
 import static org.mockito.Mockito.clearInvocations;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.inOrder;
@@ -58,14 +60,19 @@
 import static org.mockito.Mockito.verify;
 
 import android.app.ActivityManager.RunningTaskInfo;
+import android.app.IApplicationThread;
+import android.app.PendingIntent;
 import android.content.Context;
+import android.content.Intent;
 import android.os.Binder;
+import android.os.Bundle;
 import android.os.Handler;
 import android.os.IBinder;
 import android.os.Looper;
 import android.os.RemoteException;
 import android.util.ArraySet;
 import android.util.Pair;
+import android.view.IRecentsAnimationRunner;
 import android.view.Surface;
 import android.view.SurfaceControl;
 import android.view.WindowManager;
@@ -86,6 +93,7 @@
 import androidx.test.filters.SmallTest;
 import androidx.test.platform.app.InstrumentationRegistry;
 
+import com.android.server.testutils.StubTransaction;
 import com.android.wm.shell.ShellTestCase;
 import com.android.wm.shell.TestShellExecutor;
 import com.android.wm.shell.TransitionInfoBuilder;
@@ -93,6 +101,7 @@
 import com.android.wm.shell.common.DisplayLayout;
 import com.android.wm.shell.common.ShellExecutor;
 import com.android.wm.shell.common.TransactionPool;
+import com.android.wm.shell.recents.RecentsTransitionHandler;
 import com.android.wm.shell.sysui.ShellController;
 import com.android.wm.shell.sysui.ShellInit;
 import com.android.wm.shell.sysui.ShellSharedConstants;
@@ -100,6 +109,7 @@
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.mockito.Answers;
 import org.mockito.InOrder;
 
 import java.util.ArrayList;
@@ -162,8 +172,8 @@
         verify(mOrganizer, times(1)).startTransition(eq(transitToken), any());
         TransitionInfo info = new TransitionInfoBuilder(TRANSIT_OPEN)
                 .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
-        transitions.onTransitionReady(transitToken, info, mock(SurfaceControl.Transaction.class),
-                mock(SurfaceControl.Transaction.class));
+        transitions.onTransitionReady(transitToken, info, new StubTransaction(),
+                new StubTransaction());
         assertEquals(1, mDefaultHandler.activeCount());
         mDefaultHandler.finishAll();
         mMainExecutor.flushAll();
@@ -212,8 +222,8 @@
         transitions.requestStartTransition(transitToken,
                 new TransitionRequestInfo(TRANSIT_OPEN, null /* trigger */, null /* remote */));
         verify(mOrganizer, times(1)).startTransition(eq(transitToken), isNull());
-        transitions.onTransitionReady(transitToken, open, mock(SurfaceControl.Transaction.class),
-                mock(SurfaceControl.Transaction.class));
+        transitions.onTransitionReady(transitToken, open, new StubTransaction(),
+                new StubTransaction());
         assertEquals(1, mDefaultHandler.activeCount());
         assertEquals(0, testHandler.activeCount());
         mDefaultHandler.finishAll();
@@ -228,8 +238,8 @@
                 new TransitionRequestInfo(TRANSIT_OPEN, mwTaskInfo, null /* remote */));
         verify(mOrganizer, times(1)).startTransition(
                 eq(transitToken), eq(handlerWCT));
-        transitions.onTransitionReady(transitToken, open, mock(SurfaceControl.Transaction.class),
-                mock(SurfaceControl.Transaction.class));
+        transitions.onTransitionReady(transitToken, open, new StubTransaction(),
+                new StubTransaction());
         assertEquals(1, mDefaultHandler.activeCount());
         assertEquals(0, testHandler.activeCount());
         mDefaultHandler.finishAll();
@@ -246,8 +256,8 @@
                 eq(transitToken), eq(handlerWCT));
         TransitionInfo change = new TransitionInfoBuilder(TRANSIT_CHANGE)
                 .addChange(TRANSIT_CHANGE).build();
-        transitions.onTransitionReady(transitToken, change, mock(SurfaceControl.Transaction.class),
-                mock(SurfaceControl.Transaction.class));
+        transitions.onTransitionReady(transitToken, change, new StubTransaction(),
+                new StubTransaction());
         assertEquals(0, mDefaultHandler.activeCount());
         assertEquals(1, testHandler.activeCount());
         assertEquals(0, topHandler.activeCount());
@@ -284,8 +294,8 @@
         verify(mOrganizer, times(1)).startTransition(eq(transitToken), any());
         TransitionInfo info = new TransitionInfoBuilder(TRANSIT_OPEN)
                 .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
-        transitions.onTransitionReady(transitToken, info, mock(SurfaceControl.Transaction.class),
-                mock(SurfaceControl.Transaction.class));
+        transitions.onTransitionReady(transitToken, info, new StubTransaction(),
+                new StubTransaction());
         assertEquals(0, mDefaultHandler.activeCount());
         assertTrue(remoteCalled[0]);
         mDefaultHandler.finishAll();
@@ -434,8 +444,8 @@
         verify(mOrganizer, times(1)).startTransition(eq(transitToken), any());
         TransitionInfo info = new TransitionInfoBuilder(TRANSIT_OPEN)
                 .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
-        transitions.onTransitionReady(transitToken, info, mock(SurfaceControl.Transaction.class),
-                mock(SurfaceControl.Transaction.class));
+        transitions.onTransitionReady(transitToken, info, new StubTransaction(),
+                new StubTransaction());
         assertEquals(0, mDefaultHandler.activeCount());
         assertTrue(remoteCalled[0]);
         mDefaultHandler.finishAll();
@@ -484,10 +494,10 @@
         oneShot.setTransition(transitToken);
         IBinder anotherToken = new Binder();
         assertFalse(oneShot.startAnimation(anotherToken, new TransitionInfo(transitType, 0),
-                mock(SurfaceControl.Transaction.class), mock(SurfaceControl.Transaction.class),
+                new StubTransaction(), new StubTransaction(),
                 testFinish));
         assertTrue(oneShot.startAnimation(transitToken, new TransitionInfo(transitType, 0),
-                mock(SurfaceControl.Transaction.class), mock(SurfaceControl.Transaction.class),
+                new StubTransaction(), new StubTransaction(),
                 testFinish));
     }
 
@@ -501,8 +511,8 @@
                 new TransitionRequestInfo(TRANSIT_OPEN, null /* trigger */, null /* remote */));
         TransitionInfo info1 = new TransitionInfoBuilder(TRANSIT_OPEN)
                 .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
-        transitions.onTransitionReady(transitToken1, info1, mock(SurfaceControl.Transaction.class),
-                mock(SurfaceControl.Transaction.class));
+        transitions.onTransitionReady(transitToken1, info1, new StubTransaction(),
+                new StubTransaction());
         assertEquals(1, mDefaultHandler.activeCount());
 
         IBinder transitToken2 = new Binder();
@@ -510,8 +520,8 @@
                 new TransitionRequestInfo(TRANSIT_CLOSE, null /* trigger */, null /* remote */));
         TransitionInfo info2 = new TransitionInfoBuilder(TRANSIT_CLOSE)
                 .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
-        transitions.onTransitionReady(transitToken2, info2, mock(SurfaceControl.Transaction.class),
-                mock(SurfaceControl.Transaction.class));
+        transitions.onTransitionReady(transitToken2, info2, new StubTransaction(),
+                new StubTransaction());
         // default handler doesn't merge by default, so it shouldn't increment active count.
         assertEquals(1, mDefaultHandler.activeCount());
         assertEquals(0, mDefaultHandler.mergeCount());
@@ -542,8 +552,8 @@
                 new TransitionRequestInfo(TRANSIT_OPEN, null /* trigger */, null /* remote */));
         TransitionInfo info1 = new TransitionInfoBuilder(TRANSIT_OPEN)
                 .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
-        transitions.onTransitionReady(transitToken1, info1, mock(SurfaceControl.Transaction.class),
-                mock(SurfaceControl.Transaction.class));
+        transitions.onTransitionReady(transitToken1, info1, new StubTransaction(),
+                new StubTransaction());
         assertEquals(1, mDefaultHandler.activeCount());
 
         IBinder transitToken2 = new Binder();
@@ -551,8 +561,8 @@
                 new TransitionRequestInfo(TRANSIT_CLOSE, null /* trigger */, null /* remote */));
         TransitionInfo info2 = new TransitionInfoBuilder(TRANSIT_CLOSE)
                 .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
-        transitions.onTransitionReady(transitToken2, info2, mock(SurfaceControl.Transaction.class),
-                mock(SurfaceControl.Transaction.class));
+        transitions.onTransitionReady(transitToken2, info2, new StubTransaction(),
+                new StubTransaction());
         // it should still only have 1 active, but then show 1 merged
         assertEquals(1, mDefaultHandler.activeCount());
         assertEquals(1, mDefaultHandler.mergeCount());
@@ -611,8 +621,8 @@
                     new TransitionRequestInfo(TRANSIT_OPEN, null /* trigger */, null /* remote */));
             TransitionInfo info = new TransitionInfoBuilder(TRANSIT_OPEN)
                     .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
-            transitions.onTransitionReady(token, info, mock(SurfaceControl.Transaction.class),
-                    mock(SurfaceControl.Transaction.class));
+            transitions.onTransitionReady(token, info, new StubTransaction(),
+                    new StubTransaction());
             return token;
         };
 
@@ -678,8 +688,8 @@
         // queued), so continue the transition lifecycle for that.
         TransitionInfo info = new TransitionInfoBuilder(TRANSIT_OPEN)
                 .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
-        transitions.onTransitionReady(transitToken, info, mock(SurfaceControl.Transaction.class),
-                mock(SurfaceControl.Transaction.class));
+        transitions.onTransitionReady(transitToken, info, new StubTransaction(),
+                new StubTransaction());
         // At this point, if things are not working, we'd get an NPE due to attempting to merge
         // into the shellInit transition which hasn't started yet.
         assertEquals(1, mDefaultHandler.activeCount());
@@ -791,8 +801,8 @@
                 new TransitionRequestInfo(TRANSIT_OPEN, null /* trigger */, null /* remote */));
         TransitionInfo info1 = new TransitionInfoBuilder(TRANSIT_OPEN)
                 .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
-        transitions.onTransitionReady(transitToken1, info1, mock(SurfaceControl.Transaction.class),
-                mock(SurfaceControl.Transaction.class));
+        transitions.onTransitionReady(transitToken1, info1, new StubTransaction(),
+                new StubTransaction());
         assertEquals(1, mDefaultHandler.activeCount());
 
         transitions.runOnIdle(runnable2);
@@ -806,8 +816,8 @@
                 new TransitionRequestInfo(TRANSIT_CLOSE, null /* trigger */, null /* remote */));
         TransitionInfo info2 = new TransitionInfoBuilder(TRANSIT_CLOSE)
                 .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
-        transitions.onTransitionReady(transitToken2, info2, mock(SurfaceControl.Transaction.class),
-                mock(SurfaceControl.Transaction.class));
+        transitions.onTransitionReady(transitToken2, info2, new StubTransaction(),
+                new StubTransaction());
         assertEquals(1, mDefaultHandler.activeCount());
 
         mDefaultHandler.finishAll();
@@ -858,8 +868,8 @@
                 new TransitionRequestInfo(TRANSIT_OPEN, null /* trigger */, null /* remote */));
         TransitionInfo info = new TransitionInfoBuilder(TRANSIT_OPEN)
                 .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
-        SurfaceControl.Transaction startT = mock(SurfaceControl.Transaction.class);
-        SurfaceControl.Transaction finishT = mock(SurfaceControl.Transaction.class);
+        SurfaceControl.Transaction startT = new StubTransaction();
+        SurfaceControl.Transaction finishT = new StubTransaction();
         transitions.onTransitionReady(transitToken, info, startT, finishT);
 
         InOrder observerOrder = inOrder(observer);
@@ -883,8 +893,8 @@
                 new TransitionRequestInfo(TRANSIT_OPEN, null /* trigger */, null /* remote */));
         TransitionInfo info1 = new TransitionInfoBuilder(TRANSIT_OPEN)
                 .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
-        SurfaceControl.Transaction startT1 = mock(SurfaceControl.Transaction.class);
-        SurfaceControl.Transaction finishT1 = mock(SurfaceControl.Transaction.class);
+        SurfaceControl.Transaction startT1 = new StubTransaction();
+        SurfaceControl.Transaction finishT1 = new StubTransaction();
         transitions.onTransitionReady(transitToken1, info1, startT1, finishT1);
         verify(observer).onTransitionReady(transitToken1, info1, startT1, finishT1);
 
@@ -893,8 +903,8 @@
                 new TransitionRequestInfo(TRANSIT_CLOSE, null /* trigger */, null /* remote */));
         TransitionInfo info2 = new TransitionInfoBuilder(TRANSIT_CLOSE)
                 .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
-        SurfaceControl.Transaction startT2 = mock(SurfaceControl.Transaction.class);
-        SurfaceControl.Transaction finishT2 = mock(SurfaceControl.Transaction.class);
+        SurfaceControl.Transaction startT2 = new StubTransaction();
+        SurfaceControl.Transaction finishT2 = new StubTransaction();
         transitions.onTransitionReady(transitToken2, info2, startT2, finishT2);
         verify(observer, times(1)).onTransitionReady(transitToken2, info2, startT2, finishT2);
         verify(observer, times(0)).onTransitionStarting(transitToken2);
@@ -927,8 +937,8 @@
                 new TransitionRequestInfo(TRANSIT_OPEN, null /* trigger */, null /* remote */));
         TransitionInfo info1 = new TransitionInfoBuilder(TRANSIT_OPEN)
                 .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
-        SurfaceControl.Transaction startT1 = mock(SurfaceControl.Transaction.class);
-        SurfaceControl.Transaction finishT1 = mock(SurfaceControl.Transaction.class);
+        SurfaceControl.Transaction startT1 = new StubTransaction();
+        SurfaceControl.Transaction finishT1 = new StubTransaction();
         transitions.onTransitionReady(transitToken1, info1, startT1, finishT1);
 
         IBinder transitToken2 = new Binder();
@@ -936,8 +946,8 @@
                 new TransitionRequestInfo(TRANSIT_CLOSE, null /* trigger */, null /* remote */));
         TransitionInfo info2 = new TransitionInfoBuilder(TRANSIT_CLOSE)
                 .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
-        SurfaceControl.Transaction startT2 = mock(SurfaceControl.Transaction.class);
-        SurfaceControl.Transaction finishT2 = mock(SurfaceControl.Transaction.class);
+        SurfaceControl.Transaction startT2 = new StubTransaction();
+        SurfaceControl.Transaction finishT2 = new StubTransaction();
         transitions.onTransitionReady(transitToken2, info2, startT2, finishT2);
 
         InOrder observerOrder = inOrder(observer);
@@ -999,8 +1009,8 @@
                 new TransitionRequestInfo(TRANSIT_CHANGE, mwTaskInfo, null /* remote */));
         TransitionInfo change = new TransitionInfoBuilder(TRANSIT_CHANGE)
                 .addChange(TRANSIT_CHANGE).build();
-        SurfaceControl.Transaction startT1 = mock(SurfaceControl.Transaction.class);
-        SurfaceControl.Transaction finishT1 = mock(SurfaceControl.Transaction.class);
+        SurfaceControl.Transaction startT1 = new StubTransaction();
+        SurfaceControl.Transaction finishT1 = new StubTransaction();
         transitions.onTransitionReady(transitToken1, change, startT1, finishT1);
 
         // Request the second transition that should be handled by the default handler
@@ -1009,8 +1019,8 @@
                 .addChange(TRANSIT_OPEN).addChange(TRANSIT_CLOSE).build();
         transitions.requestStartTransition(transitToken2,
                 new TransitionRequestInfo(TRANSIT_OPEN, null /* trigger */, null /* remote */));
-        SurfaceControl.Transaction startT2 = mock(SurfaceControl.Transaction.class);
-        SurfaceControl.Transaction finishT2 = mock(SurfaceControl.Transaction.class);
+        SurfaceControl.Transaction startT2 = new StubTransaction();
+        SurfaceControl.Transaction finishT2 = new StubTransaction();
         transitions.onTransitionReady(transitToken2, open, startT2, finishT2);
         verify(observer).onTransitionReady(transitToken2, open, startT2, finishT2);
         verify(observer, times(0)).onTransitionStarting(transitToken2);
@@ -1019,8 +1029,8 @@
         IBinder transitToken3 = new Binder();
         transitions.requestStartTransition(transitToken3,
                 new TransitionRequestInfo(TRANSIT_OPEN, null /* trigger */, null /* remote */));
-        SurfaceControl.Transaction startT3 = mock(SurfaceControl.Transaction.class);
-        SurfaceControl.Transaction finishT3 = mock(SurfaceControl.Transaction.class);
+        SurfaceControl.Transaction startT3 = new StubTransaction();
+        SurfaceControl.Transaction finishT3 = new StubTransaction();
         transitions.onTransitionReady(transitToken3, open, startT3, finishT3);
         verify(observer, times(0)).onTransitionStarting(transitToken2);
         verify(observer).onTransitionReady(transitToken3, open, startT3, finishT3);
@@ -1045,6 +1055,104 @@
     }
 
     @Test
+    public void testTransitSleep_squashesRecents() {
+        ShellInit shellInit = new ShellInit(mMainExecutor);
+        final Transitions transitions =
+                new Transitions(mContext, shellInit, mock(ShellController.class), mOrganizer,
+                        mTransactionPool, createTestDisplayController(), mMainExecutor,
+                        mMainHandler, mAnimExecutor);
+        final RecentsTransitionHandler recentsHandler =
+                new RecentsTransitionHandler(shellInit, transitions, null);
+        transitions.replaceDefaultHandlerForTest(mDefaultHandler);
+        shellInit.init();
+
+        Transitions.TransitionObserver observer = mock(Transitions.TransitionObserver.class);
+        transitions.registerObserver(observer);
+
+        RunningTaskInfo task1 = createTaskInfo(1, WINDOWING_MODE_FULLSCREEN, ACTIVITY_TYPE_RECENTS);
+        RunningTaskInfo task2 = createTaskInfo(2);
+
+        // Start an open transition for the purpose of occupying the ready queue
+        final IBinder transitOpen1 = new Binder("transitOpen1");
+        final TransitionInfo infoOpen1 =
+                new TransitionInfoBuilder(TRANSIT_OPEN)
+                        .addChange(TRANSIT_OPEN, task1)
+                        .build();
+        mMainExecutor.execute(() -> {
+            transitions.requestStartTransition(transitOpen1, new TransitionRequestInfo(
+                        TRANSIT_OPEN, task1 /* trigger */, null /* remote */));
+            onTransitionReady(transitions, transitOpen1, infoOpen1);
+        });
+
+        // First transition on the queue should start immediately.
+        mMainExecutor.flushAll();
+        verify(observer).onTransitionReady(eq(transitOpen1), any(), any(), any());
+        verify(observer).onTransitionStarting(eq(transitOpen1));
+
+        // Start recents
+        final IRecentsAnimationRunner recentsListener =
+                mock(IRecentsAnimationRunner.class, Answers.RETURNS_DEEP_STUBS);
+        final IBinder transitRecents = recentsHandler.startRecentsTransition(
+                mock(PendingIntent.class) /* intent */,
+                mock(Intent.class) /* fillIn */,
+                new Bundle() /* options */,
+                mock(IApplicationThread.class) /* appThread */,
+                recentsListener);
+        final TransitionInfo infoRecents =
+                new TransitionInfoBuilder(TRANSIT_TO_FRONT)
+                        .addChange(TRANSIT_TO_FRONT, task1)
+                        .addChange(TRANSIT_CLOSE, task2)
+                        .build();
+        onTransitionReady(transitions, transitRecents, infoRecents);
+
+        // Start another open transition during recents
+        final IBinder transitOpen2 = new Binder("transitOpen2");
+        final TransitionInfo infoOpen2 =
+                new TransitionInfoBuilder(TRANSIT_OPEN)
+                        .addChange(TRANSIT_OPEN, task2)
+                        .addChange(TRANSIT_TO_BACK, task1)
+                        .build();
+        mMainExecutor.execute(() -> {
+            transitions.requestStartTransition(transitOpen2,  new TransitionRequestInfo(
+                        TRANSIT_OPEN, task2 /* trigger */, null /* remote */));
+            onTransitionReady(transitions, transitOpen2, infoOpen2);
+        });
+
+        // Finish testOpen1 to start processing the other transitions
+        mMainExecutor.execute(() -> {
+            mDefaultHandler.finishOne();
+        });
+        mMainExecutor.flushAll();
+
+        // Recents transition SHOULD start, and merge the open transition, which should NOT start.
+        verify(observer).onTransitionFinished(eq(transitOpen1), eq(false) /* aborted */);
+        verify(observer).onTransitionReady(eq(transitRecents), any(), any(), any());
+        verify(observer).onTransitionStarting(eq(transitRecents));
+        verify(observer).onTransitionReady(eq(transitOpen2), any(), any(), any());
+        verify(observer).onTransitionMerged(eq(transitOpen2), eq(transitRecents));
+        // verify(observer).onTransitionFinished(eq(transitOpen2), eq(true) /* aborted */);
+
+        // Go to sleep
+        final IBinder transitSleep = new Binder("transitSleep");
+        final TransitionInfo infoSleep = new TransitionInfoBuilder(TRANSIT_SLEEP).build();
+        mMainExecutor.execute(() -> {
+            transitions.requestStartTransition(transitSleep, new TransitionRequestInfo(
+                        TRANSIT_SLEEP, null /* trigger */, null /* remote */));
+            onTransitionReady(transitions, transitSleep, infoSleep);
+        });
+        mMainExecutor.flushAll();
+
+        // Recents transition should finish itself when it sees the sleep transition coming.
+        verify(observer).onTransitionFinished(eq(transitRecents), eq(false));
+        verify(observer).onTransitionFinished(eq(transitSleep), eq(false));
+    }
+
+    private void onTransitionReady(Transitions transitions, IBinder token, TransitionInfo info) {
+        transitions.onTransitionReady(token, info, new StubTransaction(),
+                new StubTransaction());
+    }
+
+    @Test
     public void testEmptyTransitionStillReportsKeyguardGoingAway() {
         Transitions transitions = createTestTransitions();
         transitions.replaceDefaultHandlerForTest(mDefaultHandler);
@@ -1056,8 +1164,8 @@
         // Make a no-op transition
         TransitionInfo info = new TransitionInfoBuilder(
                 TRANSIT_OPEN, TRANSIT_FLAG_KEYGUARD_GOING_AWAY, true /* noOp */).build();
-        transitions.onTransitionReady(transitToken, info, mock(SurfaceControl.Transaction.class),
-                mock(SurfaceControl.Transaction.class));
+        transitions.onTransitionReady(transitToken, info, new StubTransaction(),
+                new StubTransaction());
 
         // If keyguard-going-away flag set, then it shouldn't be aborted.
         assertEquals(1, mDefaultHandler.activeCount());
@@ -1397,7 +1505,7 @@
 
     private static void onTransitionReady(Transitions transitions, IBinder token) {
         transitions.onTransitionReady(token, createTransitionInfo(),
-                mock(SurfaceControl.Transaction.class), mock(SurfaceControl.Transaction.class));
+                new StubTransaction(), new StubTransaction());
     }
 
     private static TransitionInfo createTransitionInfo() {
@@ -1414,15 +1522,15 @@
     private static RunningTaskInfo createTaskInfo(int taskId, int windowingMode, int activityType) {
         RunningTaskInfo taskInfo = new RunningTaskInfo();
         taskInfo.taskId = taskId;
+        taskInfo.topActivityType = activityType;
         taskInfo.configuration.windowConfiguration.setWindowingMode(windowingMode);
         taskInfo.configuration.windowConfiguration.setActivityType(activityType);
+        taskInfo.token = mock(WindowContainerToken.class);
         return taskInfo;
     }
 
     private static RunningTaskInfo createTaskInfo(int taskId) {
-        RunningTaskInfo taskInfo = new RunningTaskInfo();
-        taskInfo.taskId = taskId;
-        return taskInfo;
+        return createTaskInfo(taskId, WINDOWING_MODE_FULLSCREEN, ACTIVITY_TYPE_STANDARD);
     }
 
     private DisplayController createTestDisplayController() {
diff --git a/services/tests/wmtests/src/com/android/server/wm/StubTransaction.java b/services/tests/servicestests/utils/com/android/server/testutils/StubTransaction.java
similarity index 98%
rename from services/tests/wmtests/src/com/android/server/wm/StubTransaction.java
rename to services/tests/servicestests/utils/com/android/server/testutils/StubTransaction.java
index 31546e8..34e8ff2 100644
--- a/services/tests/wmtests/src/com/android/server/wm/StubTransaction.java
+++ b/services/tests/servicestests/utils/com/android/server/testutils/StubTransaction.java
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.android.server.wm;
+package com.android.server.testutils;
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
@@ -30,6 +30,8 @@
 import android.view.Surface;
 import android.view.SurfaceControl;
 
+import com.android.server.testutils.StubTransaction;
+
 import java.util.HashSet;
 import java.util.concurrent.Executor;
 
diff --git a/services/tests/wmtests/src/com/android/server/wm/DimmerTests.java b/services/tests/wmtests/src/com/android/server/wm/DimmerTests.java
index 5282585e9..f235d15 100644
--- a/services/tests/wmtests/src/com/android/server/wm/DimmerTests.java
+++ b/services/tests/wmtests/src/com/android/server/wm/DimmerTests.java
@@ -36,6 +36,7 @@
 import android.view.SurfaceSession;
 
 import com.android.server.wm.SurfaceAnimator.AnimationType;
+import com.android.server.testutils.StubTransaction;
 
 import org.junit.Before;
 import org.junit.Test;
diff --git a/services/tests/wmtests/src/com/android/server/wm/LetterboxTest.java b/services/tests/wmtests/src/com/android/server/wm/LetterboxTest.java
index d400a4c..d2494ff 100644
--- a/services/tests/wmtests/src/com/android/server/wm/LetterboxTest.java
+++ b/services/tests/wmtests/src/com/android/server/wm/LetterboxTest.java
@@ -37,6 +37,8 @@
 
 import androidx.test.filters.SmallTest;
 
+import com.android.server.testutils.StubTransaction;
+
 import org.junit.Before;
 import org.junit.Test;
 import org.mockito.invocation.InvocationOnMock;
diff --git a/services/tests/wmtests/src/com/android/server/wm/SurfaceSyncGroupTest.java b/services/tests/wmtests/src/com/android/server/wm/SurfaceSyncGroupTest.java
index e30206e..c8fc6b8 100644
--- a/services/tests/wmtests/src/com/android/server/wm/SurfaceSyncGroupTest.java
+++ b/services/tests/wmtests/src/com/android/server/wm/SurfaceSyncGroupTest.java
@@ -30,6 +30,8 @@
 
 import androidx.test.filters.SmallTest;
 
+import com.android.server.testutils.StubTransaction;
+
 import org.junit.Before;
 import org.junit.Test;
 
diff --git a/services/tests/wmtests/src/com/android/server/wm/SyncEngineTests.java b/services/tests/wmtests/src/com/android/server/wm/SyncEngineTests.java
index ddd630e..a3a3684 100644
--- a/services/tests/wmtests/src/com/android/server/wm/SyncEngineTests.java
+++ b/services/tests/wmtests/src/com/android/server/wm/SyncEngineTests.java
@@ -42,6 +42,7 @@
 
 import androidx.test.filters.SmallTest;
 
+import com.android.server.testutils.StubTransaction;
 import com.android.server.testutils.TestHandler;
 
 import org.junit.Before;
diff --git a/services/tests/wmtests/src/com/android/server/wm/SystemServicesTestRule.java b/services/tests/wmtests/src/com/android/server/wm/SystemServicesTestRule.java
index 013c6d5..7edfd9a 100644
--- a/services/tests/wmtests/src/com/android/server/wm/SystemServicesTestRule.java
+++ b/services/tests/wmtests/src/com/android/server/wm/SystemServicesTestRule.java
@@ -88,6 +88,7 @@
 import com.android.server.policy.PermissionPolicyInternal;
 import com.android.server.policy.WindowManagerPolicy;
 import com.android.server.statusbar.StatusBarManagerInternal;
+import com.android.server.testutils.StubTransaction;
 import com.android.server.uri.UriGrantsManagerInternal;
 
 import org.junit.rules.TestRule;
diff --git a/services/tests/wmtests/src/com/android/server/wm/WindowAnimationSpecTest.java b/services/tests/wmtests/src/com/android/server/wm/WindowAnimationSpecTest.java
index e2f1334..608d7c9 100644
--- a/services/tests/wmtests/src/com/android/server/wm/WindowAnimationSpecTest.java
+++ b/services/tests/wmtests/src/com/android/server/wm/WindowAnimationSpecTest.java
@@ -38,6 +38,8 @@
 
 import androidx.test.filters.SmallTest;
 
+import com.android.server.testutils.StubTransaction;
+
 import org.junit.Test;
 
 /**
diff --git a/services/tests/wmtests/src/com/android/server/wm/WindowContainerThumbnailTest.java b/services/tests/wmtests/src/com/android/server/wm/WindowContainerThumbnailTest.java
index 2ae1172..849072e 100644
--- a/services/tests/wmtests/src/com/android/server/wm/WindowContainerThumbnailTest.java
+++ b/services/tests/wmtests/src/com/android/server/wm/WindowContainerThumbnailTest.java
@@ -28,6 +28,8 @@
 
 import androidx.test.filters.SmallTest;
 
+import com.android.server.testutils.StubTransaction;
+
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
diff --git a/services/tests/wmtests/src/com/android/server/wm/WindowStateTests.java b/services/tests/wmtests/src/com/android/server/wm/WindowStateTests.java
index 460a603..ee1afcf 100644
--- a/services/tests/wmtests/src/com/android/server/wm/WindowStateTests.java
+++ b/services/tests/wmtests/src/com/android/server/wm/WindowStateTests.java
@@ -110,6 +110,8 @@
 
 import androidx.test.filters.SmallTest;
 
+import com.android.server.testutils.StubTransaction;
+
 import org.junit.Test;
 import org.junit.runner.RunWith;