diff --git a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeAdaptiveMediaPeriod.java b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeAdaptiveMediaPeriod.java
index 3dcf551943..a4c9abb24e 100644
--- a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeAdaptiveMediaPeriod.java
+++ b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeAdaptiveMediaPeriod.java
@@ -84,6 +84,14 @@ public class FakeAdaptiveMediaPeriod extends FakeMediaPeriod
     return returnPositionUs;
   }
 
+  @Override
+  public void discardBuffer(long positionUs, boolean toKeyframe) {
+    super.discardBuffer(positionUs, toKeyframe);
+    for (ChunkSampleStream<FakeChunkSource> sampleStream : sampleStreams) {
+      sampleStream.discardBuffer(positionUs, toKeyframe);
+    }
+  }
+
   @Override
   public long getBufferedPositionUs() {
     super.getBufferedPositionUs();
diff --git a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeSimpleExoPlayer.java b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeSimpleExoPlayer.java
index 0358e5d980..1e7e0cd933 100644
--- a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeSimpleExoPlayer.java
+++ b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeSimpleExoPlayer.java
@@ -364,6 +364,7 @@ public class FakeSimpleExoPlayer extends SimpleExoPlayer {
     public void run() {
       try {
         maybeContinueLoading();
+        mediaPeriod.discardBuffer(rendererPositionUs, /* toKeyframe= */ false);
         boolean allRenderersEnded = true;
         boolean allRenderersReadyOrEnded = true;
         if (playbackState == Player.STATE_READY) {