Clean-up ExoHostedTest/HostActivity.

This change clearly seperates the hosting of a test (HostActivity) from
the internals of hosting an ExoPlayer lifecycle (ExoHostedTest).

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=163967960

testutils/src/main/java/com/google/android/exoplayer2/testutil/ExoHostedTest.java

@@ -73,7 +73,7 @@ public abstract class ExoHostedTest implements HostedTest, Player.EventListener,
   private final long expectedPlayingTimeMs;
   private final DecoderCounters videoDecoderCounters;
   private final DecoderCounters audioDecoderCounters;
-  private final ConditionVariable playerFinished;
+  private final ConditionVariable testFinished;
 
   private ActionSchedule pendingSchedule;
   private Handler actionHandler;
@@ -116,7 +116,7 @@ public abstract class ExoHostedTest implements HostedTest, Player.EventListener,
     this.tag = tag;
     this.expectedPlayingTimeMs = expectedPlayingTimeMs;
     this.failOnPlayerError = failOnPlayerError;
-    this.playerFinished = new ConditionVariable();
+    this.testFinished = new ConditionVariable();
     this.videoDecoderCounters = new DecoderCounters();
     this.audioDecoderCounters = new DecoderCounters();
   }
@@ -172,16 +172,13 @@ public abstract class ExoHostedTest implements HostedTest, Player.EventListener,
   }
 
   @Override
-  public final boolean blockUntilEnded(long timeoutMs) {
-    return playerFinished.block(timeoutMs);
+  public final boolean blockUntilStopped(long timeoutMs) {
+    return testFinished.block(timeoutMs);
   }
 
   @Override
-  public final void onStop() {
-    actionHandler.removeCallbacksAndMessages(null);
-    sourceDurationMs = player.getDuration();
-    player.release();
-    player = null;
+  public final boolean forceStop() {
+    return stopTest();
   }
 
   @Override
@@ -222,7 +219,7 @@ public abstract class ExoHostedTest implements HostedTest, Player.EventListener,
     playerWasPrepared |= playbackState != Player.STATE_IDLE;
     if (playbackState == Player.STATE_ENDED
         || (playbackState == Player.STATE_IDLE && playerWasPrepared)) {
-      playerFinished.open();
+      stopTest();
     }
     boolean playing = playWhenReady && playbackState == Player.STATE_READY;
     if (!this.playing && playing) {
@@ -337,6 +334,25 @@ public abstract class ExoHostedTest implements HostedTest, Player.EventListener,
 
   // Internal logic
 
+  private boolean stopTest() {
+    if (player == null) {
+      return false;
+    }
+    actionHandler.removeCallbacksAndMessages(null);
+    sourceDurationMs = player.getDuration();
+    player.release();
+    player = null;
+    // We post opening of the finished condition so that any events posted to the main thread as a
+    // result of player.release() are guaranteed to be handled before the test returns.
+    actionHandler.post(new Runnable() {
+      @Override
+      public void run() {
+        testFinished.open();
+      }
+    });
+    return true;
+  }
+
   protected DrmSessionManager<FrameworkMediaCrypto> buildDrmSessionManager(String userAgent) {
     // Do nothing. Interested subclasses may override.
     return null;

testutils/src/main/java/com/google/android/exoplayer2/testutil/HostActivity.java

@@ -56,21 +56,20 @@ public final class HostActivity extends Activity implements SurfaceHolder.Callba
     void onStart(HostActivity host, Surface surface);
 
     /**
-     * Called on the main thread to block until the test has stopped or {@link #onStop()} is called.
+     * Called on the main thread to block until the test has stopped or {@link #forceStop()} is
+     * called.
      *
      * @param timeoutMs The maximum time to block in milliseconds.
      * @return Whether the test has stopped successful.
      */
-    boolean blockUntilEnded(long timeoutMs);
+    boolean blockUntilStopped(long timeoutMs);
 
     /**
-     * Called on the main thread when the test is stopped.
-     * <p>
-     * The test will be stopped when {@link #blockUntilEnded(long)} returns, if the
-     * {@link HostActivity} has been paused, or if the {@link HostActivity}'s {@link Surface} has
-     * been destroyed.
+     * Called on the main thread to force stop the test (if it is not stopped already).
+     *
+     * @return Whether the test was forced stopped.
      */
-    void onStop();
+    boolean forceStop();
 
     /**
      * Called on the test thread after the test has finished and been stopped.
@@ -89,7 +88,8 @@ public final class HostActivity extends Activity implements SurfaceHolder.Callba
 
   private HostedTest hostedTest;
   private boolean hostedTestStarted;
-  private boolean forcedFinished;
+  private ConditionVariable hostedTestStartedCondition;
+  private boolean forcedStopped;
 
   /**
    * Executes a {@link HostedTest} inside the host.
@@ -109,34 +109,31 @@ public final class HostActivity extends Activity implements SurfaceHolder.Callba
    * @param timeoutMs The number of milliseconds to wait for the test to finish.
    * @param failOnTimeout Whether the test fails when the timeout is exceeded.
    */
-  public void runTest(HostedTest hostedTest, long timeoutMs, boolean failOnTimeout) {
+  public void runTest(final HostedTest hostedTest, long timeoutMs, boolean failOnTimeout) {
     Assertions.checkArgument(timeoutMs > 0);
     Assertions.checkState(Thread.currentThread() != getMainLooper().getThread());
-
     Assertions.checkState(this.hostedTest == null);
-    this.hostedTest = Assertions.checkNotNull(hostedTest);
+    Assertions.checkNotNull(hostedTest);
+    hostedTestStartedCondition = new ConditionVariable();
+    forcedStopped = false;
     hostedTestStarted = false;
-    forcedFinished = false;
 
-    final ConditionVariable testStarted = new ConditionVariable();
     runOnUiThread(new Runnable() {
       @Override
       public void run() {
+        HostActivity.this.hostedTest = hostedTest;
         maybeStartHostedTest();
-        testStarted.open();
       }
     });
-    testStarted.block();
+    hostedTestStartedCondition.block();
 
-    if (hostedTest.blockUntilEnded(timeoutMs)) {
-      hostedTest.onStop();
-      if (!forcedFinished) {
-        Log.d(TAG, "Test finished. Checking pass conditions.");
+    if (hostedTest.blockUntilStopped(timeoutMs)) {
+      if (!forcedStopped) {
+        Log.d(TAG, "Checking test pass conditions.");
         hostedTest.onFinished();
-        this.hostedTest = null;
         Log.d(TAG, "Pass conditions checked.");
       } else {
-        String message = "Test released before it finished. Activity may have been paused whilst "
+        String message = "Test force stopped. Activity may have been paused whilst "
             + "test was in progress.";
         Log.e(TAG, message);
         fail(message);
@@ -147,8 +144,8 @@ public final class HostActivity extends Activity implements SurfaceHolder.Callba
       if (failOnTimeout) {
         fail(message);
       }
-      maybeStopHostedTest();
     }
+    this.hostedTest = null;
   }
 
   // Activity lifecycle
@@ -176,12 +173,6 @@ public final class HostActivity extends Activity implements SurfaceHolder.Callba
   }
 
   @Override
-  public void onResume() {
-    super.onResume();
-    maybeStartHostedTest();
-  }
-
-  @Override
   public void onPause() {
     super.onPause();
     maybeStopHostedTest();
@@ -224,14 +215,13 @@ public final class HostActivity extends Activity implements SurfaceHolder.Callba
       hostedTestStarted = true;
       Log.d(TAG, "Starting test.");
       hostedTest.onStart(this, surface);
+      hostedTestStartedCondition.open();
     }
   }
 
   private void maybeStopHostedTest() {
-    if (hostedTest != null && hostedTestStarted) {
-      forcedFinished = true;
-      hostedTest.onStop();
-      hostedTest = null;
+    if (hostedTest != null && hostedTestStarted && !forcedStopped) {
+      forcedStopped = hostedTest.forceStop();
     }
   }