From 6dd9a627c166c97555a6c7c23d0db743f5e73b26 Mon Sep 17 00:00:00 2001
From: Yunfan Chen <yunfanc@google.com>
Date: Mon, 18 Feb 2019 15:12:33 +0900
Subject: [PATCH] Fix flaky testForAllWinddow

It was flaky because the exiting window may be removed before the
assertion. Prevent it from removal can fix it.

During the setup, while window get created, there are
WindowSurfacePlacer traversal being posted to mAnimationHandler. This
could happen while we run the test. During the traversal, all exiting
window will be removed if possible, and the test window will get
removed.

Wait until the traversal finished can fix the issue.

Bug: 77772044
Bug: 74078662
Bug: 124088319
Test: atest DisplayContentTests#testForAllWindows
Change-Id: I7f14605d3bd4a548755b7e88b0294168ab46ec7b
---
 .../src/com/android/server/wm/DisplayContentTests.java   | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/services/tests/wmtests/src/com/android/server/wm/DisplayContentTests.java b/services/tests/wmtests/src/com/android/server/wm/DisplayContentTests.java
index a62bc713db40a..2452ef0425e1d 100644
--- a/services/tests/wmtests/src/com/android/server/wm/DisplayContentTests.java
+++ b/services/tests/wmtests/src/com/android/server/wm/DisplayContentTests.java
@@ -61,7 +61,6 @@ import android.os.SystemClock;
 import android.platform.test.annotations.Presubmit;
 import android.util.DisplayMetrics;
 import android.view.DisplayCutout;
-import android.view.DisplayInfo;
 import android.view.Gravity;
 import android.view.MotionEvent;
 import android.view.Surface;
@@ -87,18 +86,22 @@ import java.util.List;
  * Tests for the {@link DisplayContent} class.
  *
  * Build/Install/Run:
- *  atest FrameworksServicesTests:DisplayContentTests
+ *  atest WmTests:DisplayContentTests
  */
 @SmallTest
 @Presubmit
 public class DisplayContentTests extends WindowTestsBase {
 
     @Test
-    @FlakyTest(bugId = 77772044)
+    @FlakyTest(detail = "Promote to presubmit when shown to be stable.")
     public void testForAllWindows() {
         final WindowState exitingAppWindow = createWindow(null, TYPE_BASE_APPLICATION,
                 mDisplayContent, "exiting app");
         final AppWindowToken exitingAppToken = exitingAppWindow.mAppToken;
+        // Wait until everything in animation handler get executed to prevent the exiting window
+        // from being removed during WindowSurfacePlacer Traversal.
+        waitUntilHandlersIdle();
+
         exitingAppToken.mIsExiting = true;
         exitingAppToken.getTask().mStack.mExitingAppTokens.add(exitingAppToken);