[ShellTransit] Stabilize QuickSwitch test since Launcher can resumed.

QuickSwitch can resume Launcher activity due to transient launch when
shell transition is enabled, waiting for the Launcher leave resume
stage to make the test stable.

Bug: 263907455
Test: atest TaplTestsQuickstep#testQuickSwitchToPreviousAppForTablet
Change-Id: I2e6e0511cba51f4634ccf3da454e4be1dd93ffd1
diff --git a/quickstep/tests/src/com/android/quickstep/TaplTestsQuickstep.java b/quickstep/tests/src/com/android/quickstep/TaplTestsQuickstep.java
index 9a2fcc0..9f34775 100644
--- a/quickstep/tests/src/com/android/quickstep/TaplTestsQuickstep.java
+++ b/quickstep/tests/src/com/android/quickstep/TaplTestsQuickstep.java
@@ -262,6 +262,19 @@
         return launchedAppState;
     }
 
+    private void quickSwitchToPreviousAppAndAssert(boolean toRight) {
+        final LaunchedAppState launchedAppState = getAndAssertLaunchedApp();
+        if (toRight) {
+            launchedAppState.quickSwitchToPreviousApp();
+        } else {
+            launchedAppState.quickSwitchToPreviousAppSwipeLeft();
+        }
+
+        // While enable shell transition, Launcher can be resumed due to transient launch.
+        waitForLauncherCondition("Launcher shouldn't stay in resume forever",
+                this::isInLaunchedApp, 3000 /* timeout */);
+    }
+
     @Test
     @PortraitLandscape
     public void testAllAppsFromHome() throws Exception {
@@ -288,13 +301,11 @@
         startTestActivity(3);
         startTestActivity(4);
 
-        LaunchedAppState launchedAppState = getAndAssertLaunchedApp();
-        launchedAppState.quickSwitchToPreviousApp();
+        quickSwitchToPreviousAppAndAssert(true /* toRight */);
         assertTrue("The first app we should have quick switched to is not running",
                 isTestActivityRunning(3));
 
-        launchedAppState = getAndAssertLaunchedApp();
-        launchedAppState.quickSwitchToPreviousApp();
+        quickSwitchToPreviousAppAndAssert(true /* toRight */);
         if (mLauncher.getNavigationModel() == NavigationModel.THREE_BUTTON) {
             // 3-button mode toggles between 2 apps, rather than going back further.
             assertTrue("Second quick switch should have returned to the first app.",
@@ -303,12 +314,12 @@
             assertTrue("The second app we should have quick switched to is not running",
                     isTestActivityRunning(2));
         }
-        launchedAppState = getAndAssertLaunchedApp();
-        launchedAppState.quickSwitchToPreviousAppSwipeLeft();
+
+        quickSwitchToPreviousAppAndAssert(false /* toRight */);
         assertTrue("The 2nd app we should have quick switched to is not running",
                 isTestActivityRunning(3));
 
-        launchedAppState = getAndAssertLaunchedApp();
+        final LaunchedAppState launchedAppState = getAndAssertLaunchedApp();
         launchedAppState.switchToOverview();
     }
 
@@ -327,8 +338,10 @@
         launchedAppState.assertTaskbarHidden();
 
         // Quick-switch to the test app with swiping to right.
-        launchedAppState.quickSwitchToPreviousApp();
+        quickSwitchToPreviousAppAndAssert(true /* toRight */);
 
+        assertTrue("The first app we should have quick switched to is not running",
+                isTestActivityRunning(2));
         // Expect task bar visible when the launched app was the test activity.
         launchedAppState = getAndAssertLaunchedApp();
         launchedAppState.assertTaskbarVisible();