From bbd9da86bfbded37d4e7f4b8036791ca0a13ad89 Mon Sep 17 00:00:00 2001
From: Hugo Benichi <hugobenichi@google.com>
Date: Tue, 15 Nov 2016 13:42:34 +0900
Subject: [PATCH] ConnectivityServiceTest: fix testAvoidBadWifiSettings

This patch introduces an assertEventuallyThat helper function in
ConnectivityServiceTest which given a boolean function retries until the
function returns true or until a maximum retry time is reached.

This function is used to fix flakyness of testAvoidBadWifiSetting where
the Message posted by reevaluate() could reach the Handler's
MessageQueue after waitForIdle takes effect, resulting in the test to
fail.

Instead of fixing the flakyness by introdcing hard sleep times,
assertEventuallyThat is used to reduce the overall test time.

With this change the test has been observed to pass with 100% success
rate over 50000 invocations.

Test: $ runtest frameworks-net
Bug: 32561414

(cherry picked from commit ccf7f00258c3c8dbdb6a11a5e150e917e82c8ccf)

Change-Id: If41a24989d5f65aeb439f68741f511b5eb53b18d
---
 .../server/ConnectivityServiceTest.java       | 22 ++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/tests/net/java/com/android/server/ConnectivityServiceTest.java b/tests/net/java/com/android/server/ConnectivityServiceTest.java
index bc685f27bf..4b3f99277e 100644
--- a/tests/net/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/net/java/com/android/server/ConnectivityServiceTest.java
@@ -91,6 +91,7 @@ import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.BooleanSupplier;
 
 /**
  * Tests for {@link ConnectivityService}.
@@ -622,7 +623,7 @@ public class ConnectivityServiceTest extends AndroidTestCase {
     }
 
     private class WrappedAvoidBadWifiTracker extends AvoidBadWifiTracker {
-        public boolean configRestrictsAvoidBadWifi;
+        public volatile boolean configRestrictsAvoidBadWifi;
 
         public WrappedAvoidBadWifiTracker(Context c, Handler h, Runnable r) {
             super(c, h, r);
@@ -2180,7 +2181,7 @@ public class ConnectivityServiceTest extends AndroidTestCase {
             tracker.reevaluate();
             mService.waitForIdle();
             String msg = String.format("config=false, setting=%s", values[i]);
-            assertTrue(msg, mService.avoidBadWifi());
+            assertEventuallyTrue(() -> mService.avoidBadWifi(), 50);
             assertFalse(msg, tracker.shouldNotifyWifiUnvalidated());
         }
 
@@ -2189,19 +2190,19 @@ public class ConnectivityServiceTest extends AndroidTestCase {
         Settings.Global.putInt(cr, settingName, 0);
         tracker.reevaluate();
         mService.waitForIdle();
-        assertFalse(mService.avoidBadWifi());
+        assertEventuallyTrue(() -> !mService.avoidBadWifi(), 50);
         assertFalse(tracker.shouldNotifyWifiUnvalidated());
 
         Settings.Global.putInt(cr, settingName, 1);
         tracker.reevaluate();
         mService.waitForIdle();
-        assertTrue(mService.avoidBadWifi());
+        assertEventuallyTrue(() -> mService.avoidBadWifi(), 50);
         assertFalse(tracker.shouldNotifyWifiUnvalidated());
 
         Settings.Global.putString(cr, settingName, null);
         tracker.reevaluate();
         mService.waitForIdle();
-        assertFalse(mService.avoidBadWifi());
+        assertEventuallyTrue(() -> !mService.avoidBadWifi(), 50);
         assertTrue(tracker.shouldNotifyWifiUnvalidated());
     }
 
@@ -2418,6 +2419,17 @@ public class ConnectivityServiceTest extends AndroidTestCase {
         networkCallback.assertNoCallback();
     }
 
+    public void assertEventuallyTrue(BooleanSupplier fn, long maxWaitingTimeMs) throws Exception {
+        long start = SystemClock.elapsedRealtime();
+        while (SystemClock.elapsedRealtime() <= start + maxWaitingTimeMs) {
+            if (fn.getAsBoolean()) {
+                return;
+            }
+            Thread.sleep(10);
+        }
+        assertTrue(fn.getAsBoolean());
+    }
+
     private static class TestKeepaliveCallback extends PacketKeepaliveCallback {
 
         public static enum CallbackType { ON_STARTED, ON_STOPPED, ON_ERROR };