From 3edcde295326db07520ed5eedde087c24c16dfd0 Mon Sep 17 00:00:00 2001
From: Daichi Hirono <hirono@google.com>
Date: Tue, 12 Apr 2016 11:29:07 +0900
Subject: [PATCH] Fix flakiness DocumentLoader#testCancelTask.

For testing, we use blockDocument and unblockDocument test mehtods to
control flow of DocumentLoader's background thread.
Previously testCancelTask may exit before the background thread goes
back from blocking, which causes InterruptedException.

Fixes: 28125289
Change-Id: Id03826733c5b6f1da66b9280838eb1d2897ed5fc
---
 .../src/com/android/mtp/DocumentLoader.java     |  7 ++++---
 .../src/com/android/mtp/DocumentLoaderTest.java | 17 +++++++++++------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/packages/MtpDocumentsProvider/src/com/android/mtp/DocumentLoader.java b/packages/MtpDocumentsProvider/src/com/android/mtp/DocumentLoader.java
index 329afdd4f17cd..6ed4ea1db4994 100644
--- a/packages/MtpDocumentsProvider/src/com/android/mtp/DocumentLoader.java
+++ b/packages/MtpDocumentsProvider/src/com/android/mtp/DocumentLoader.java
@@ -196,9 +196,10 @@ class DocumentLoader implements AutoCloseable {
                 }
                 task.loadObjectInfoList(NUM_LOADING_ENTRIES);
                 final boolean shouldNotify =
-                        task.mLastNotified.getTime() <
-                        new Date().getTime() - NOTIFY_PERIOD_MS ||
-                        task.getState() != LoaderTask.STATE_LOADING;
+                        task.getState() != LoaderTask.STATE_CANCELLED &&
+                        (task.mLastNotified.getTime() <
+                         new Date().getTime() - NOTIFY_PERIOD_MS ||
+                         task.getState() != LoaderTask.STATE_LOADING);
                 if (shouldNotify) {
                     task.notify(mResolver);
                 }
diff --git a/packages/MtpDocumentsProvider/tests/src/com/android/mtp/DocumentLoaderTest.java b/packages/MtpDocumentsProvider/tests/src/com/android/mtp/DocumentLoaderTest.java
index 60dd7e16a1d9d..a3c6bd77cefbd 100644
--- a/packages/MtpDocumentsProvider/tests/src/com/android/mtp/DocumentLoaderTest.java
+++ b/packages/MtpDocumentsProvider/tests/src/com/android/mtp/DocumentLoaderTest.java
@@ -143,9 +143,9 @@ public class DocumentLoaderTest extends AndroidTestCase {
         }
     }
 
-    public void testCancelTask() throws IOException, InterruptedException {
+    public void testCancelTask() throws IOException, InterruptedException, TimeoutException {
         setUpDocument(mManager,
-                DocumentLoader.NUM_INITIAL_ENTRIES + DocumentLoader.NUM_LOADING_ENTRIES + 1);
+                DocumentLoader.NUM_INITIAL_ENTRIES + 1);
 
         // Block the first iteration in the background thread.
         mManager.blockDocument(
@@ -155,19 +155,24 @@ public class DocumentLoaderTest extends AndroidTestCase {
                 MtpDocumentsProvider.DEFAULT_DOCUMENT_PROJECTION, mParentIdentifier)) {
             assertTrue(cursor.getExtras().getBoolean(DocumentsContract.EXTRA_LOADING));
         }
-        Thread.sleep(DocumentLoader.NOTIFY_PERIOD_MS);
+
+        final Uri uri = DocumentsContract.buildChildDocumentsUri(
+                MtpDocumentsProvider.AUTHORITY, mParentIdentifier.mDocumentId);
+        assertEquals(0, mResolver.getChangeCount(uri));
 
         // Clear task while the first iteration is being blocked.
+        mLoader.cancelTask(mParentIdentifier);
         mManager.unblockDocument(
                 0, DocumentLoader.NUM_INITIAL_ENTRIES + 1);
-        mLoader.cancelTask(mParentIdentifier);
-
-        Thread.sleep(DocumentLoader.NOTIFY_PERIOD_MS * 2);
+        Thread.sleep(DocumentLoader.NOTIFY_PERIOD_MS);
+        assertEquals(0, mResolver.getChangeCount(uri));
 
         // Check if it's OK to query invalidated task.
         try (final Cursor cursor = mLoader.queryChildDocuments(
                 MtpDocumentsProvider.DEFAULT_DOCUMENT_PROJECTION, mParentIdentifier)) {
+            assertTrue(cursor.getExtras().getBoolean(DocumentsContract.EXTRA_LOADING));
         }
+        mResolver.waitForNotification(uri, 1);
     }
 
     private void setUpLoader() {