diff --git a/library/common/src/main/java/com/google/android/exoplayer2/util/HandlerWrapper.java b/library/common/src/main/java/com/google/android/exoplayer2/util/HandlerWrapper.java
index 637db2fe0d..8247447d93 100644
--- a/library/common/src/main/java/com/google/android/exoplayer2/util/HandlerWrapper.java
+++ b/library/common/src/main/java/com/google/android/exoplayer2/util/HandlerWrapper.java
@@ -76,4 +76,7 @@ public interface HandlerWrapper {
 
   /** See {@link Handler#postDelayed(Runnable, long)}. */
   boolean postDelayed(Runnable runnable, long delayMs);
+
+  /** See {@link android.os.Handler#postAtFrontOfQueue(Runnable)}. */
+  boolean postAtFrontOfQueue(Runnable runnable);
 }
diff --git a/library/common/src/main/java/com/google/android/exoplayer2/util/SystemHandlerWrapper.java b/library/common/src/main/java/com/google/android/exoplayer2/util/SystemHandlerWrapper.java
index a595245bc8..ecb5ad64b1 100644
--- a/library/common/src/main/java/com/google/android/exoplayer2/util/SystemHandlerWrapper.java
+++ b/library/common/src/main/java/com/google/android/exoplayer2/util/SystemHandlerWrapper.java
@@ -110,6 +110,11 @@ import java.util.List;
     return handler.postDelayed(runnable, delayMs);
   }
 
+  @Override
+  public boolean postAtFrontOfQueue(Runnable runnable) {
+    return handler.postAtFrontOfQueue(runnable);
+  }
+
   private static SystemMessage obtainSystemMessage() {
     synchronized (messagePool) {
       return messagePool.isEmpty()
diff --git a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeChunkSource.java b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeChunkSource.java
index cc48c30690..41dd691329 100644
--- a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeChunkSource.java
+++ b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeChunkSource.java
@@ -35,18 +35,14 @@ import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.MimeTypes;
 import java.util.List;
 
-/**
- * Fake {@link ChunkSource} with adaptive media chunks of a given duration.
- */
-public final class FakeChunkSource implements ChunkSource {
+/** Fake {@link ChunkSource} with adaptive media chunks of a given duration. */
+public class FakeChunkSource implements ChunkSource {
 
-  /**
-   * Factory for a {@link FakeChunkSource}.
-   */
-  public static final class Factory {
+  /** Factory for a {@link FakeChunkSource}. */
+  public static class Factory {
 
-    private final FakeAdaptiveDataSet.Factory dataSetFactory;
-    private final FakeDataSource.Factory dataSourceFactory;
+    protected final FakeAdaptiveDataSet.Factory dataSetFactory;
+    protected final FakeDataSource.Factory dataSourceFactory;
 
     public Factory(FakeAdaptiveDataSet.Factory dataSetFactory,
         FakeDataSource.Factory dataSourceFactory) {
@@ -61,13 +57,12 @@ public final class FakeChunkSource implements ChunkSource {
       FakeAdaptiveDataSet dataSet =
           dataSetFactory.createDataSet(trackSelection.getTrackGroup(), durationUs);
       dataSourceFactory.setFakeDataSet(dataSet);
-      DataSource dataSource = dataSourceFactory.createDataSource();
+      FakeDataSource dataSource = dataSourceFactory.createDataSource();
       if (transferListener != null) {
         dataSource.addTransferListener(transferListener);
       }
       return new FakeChunkSource(trackSelection, dataSource, dataSet);
     }
-
   }
 
   private final ExoTrackSelection trackSelection;
diff --git a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeClock.java b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeClock.java
index 7bce01f5ce..59a06fc6f6 100644
--- a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeClock.java
+++ b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeClock.java
@@ -27,6 +27,7 @@ import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.util.Clock;
 import com.google.android.exoplayer2.util.HandlerWrapper;
 import com.google.common.collect.ComparisonChain;
+import com.google.common.collect.Ordering;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashSet;
@@ -309,7 +310,10 @@ public class FakeClock implements Clock {
     public int compareTo(HandlerMessage other) {
       return ComparisonChain.start()
           .compare(this.timeMs, other.timeMs)
-          .compare(this.messageId, other.messageId)
+          .compare(
+              this.messageId,
+              other.messageId,
+              timeMs == Long.MIN_VALUE ? Ordering.natural().reverse() : Ordering.natural())
           .result();
     }
   }
@@ -412,8 +416,19 @@ public class FakeClock implements Clock {
 
     @Override
     public boolean postDelayed(Runnable runnable, long delayMs) {
+      postRunnableAtTime(runnable, uptimeMillis() + delayMs);
+      return true;
+    }
+
+    @Override
+    public boolean postAtFrontOfQueue(Runnable runnable) {
+      postRunnableAtTime(runnable, /* timeMs= */ Long.MIN_VALUE);
+      return true;
+    }
+
+    private void postRunnableAtTime(Runnable runnable, long timeMs) {
       new HandlerMessage(
-              uptimeMillis() + delayMs,
+              timeMs,
               /* handler= */ this,
               /* what= */ 0,
               /* arg1= */ 0,
@@ -421,7 +436,6 @@ public class FakeClock implements Clock {
               /* obj= */ null,
               runnable)
           .sendToTarget();
-      return true;
     }
   }
 }
diff --git a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeDataSource.java b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeDataSource.java
index 5f858bea99..d517fd4fde 100644
--- a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeDataSource.java
+++ b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeDataSource.java
@@ -210,6 +210,7 @@ public class FakeDataSource extends BaseDataSource {
       transferEnded();
     }
     fakeData = null;
+    onClosed();
   }
 
   /**
@@ -227,8 +228,13 @@ public class FakeDataSource extends BaseDataSource {
     return sourceOpened;
   }
 
+  /** Called when data is being read. */
   protected void onDataRead(int bytesRead) throws IOException {
     // Do nothing. Can be overridden.
   }
 
+  /** Called when the source is closed. */
+  protected void onClosed() {
+    // Do nothing. Can be overridden.
+  }
 }
diff --git a/testutils/src/test/java/com/google/android/exoplayer2/testutil/FakeClockTest.java b/testutils/src/test/java/com/google/android/exoplayer2/testutil/FakeClockTest.java
index 28e57d8e66..bcd6fa902e 100644
--- a/testutils/src/test/java/com/google/android/exoplayer2/testutil/FakeClockTest.java
+++ b/testutils/src/test/java/com/google/android/exoplayer2/testutil/FakeClockTest.java
@@ -143,15 +143,17 @@ public final class FakeClockTest {
 
     handler.obtainMessage(/* what= */ 1).sendToTarget();
     handler.sendMessageAtFrontOfQueue(handler.obtainMessage(/* what= */ 2));
-    handler.obtainMessage(/* what= */ 3).sendToTarget();
+    handler.sendMessageAtFrontOfQueue(handler.obtainMessage(/* what= */ 3));
+    handler.obtainMessage(/* what= */ 4).sendToTarget();
     ShadowLooper.idleMainLooper();
     shadowOf(handler.getLooper()).idle();
 
     assertThat(callback.messages)
         .containsExactly(
+            new MessageData(/* what= */ 3, /* arg1= */ 0, /* arg2= */ 0, /* obj=*/ null),
             new MessageData(/* what= */ 2, /* arg1= */ 0, /* arg2= */ 0, /* obj=*/ null),
             new MessageData(/* what= */ 1, /* arg1= */ 0, /* arg2= */ 0, /* obj=*/ null),
-            new MessageData(/* what= */ 3, /* arg1= */ 0, /* arg2= */ 0, /* obj=*/ null))
+            new MessageData(/* what= */ 4, /* arg1= */ 0, /* arg2= */ 0, /* obj=*/ null))
         .inOrder();
   }