Check bundles in MediaItem to verify keys are skipped

Added another check in each of these tests to make sure we don't add keys to bundle for fields with default values.

Also fixed comments of similar changes in `AdPlaybackStateTest` and `MediaMetadataTest`.

PiperOrigin-RevId: 499463581

libraries/common/src/test/java/androidx/media3/common/AdPlaybackStateTest.java

@@ -421,13 +421,12 @@ public void adPlaybackStateWithNoAds_toBundleSkipsDefaultValues_fromBundleRestor
 
     Bundle adPlaybackStateWithNoAdsBundle = adPlaybackStateWithNoAds.toBundle();
 
-    // check Bundle created above, contains no keys.
+    // Check that default values are skipped when bundling.
     assertThat(adPlaybackStateWithNoAdsBundle.keySet()).isEmpty();
 
     AdPlaybackState adPlaybackStateWithNoAdsFromBundle =
         AdPlaybackState.CREATOR.fromBundle(adPlaybackStateWithNoAdsBundle);
 
-    // check object retrieved from adPlaybackStateWithNoAdsBundle is equal to AdPlaybackState.NONE
     assertThat(adPlaybackStateWithNoAdsFromBundle.adsId).isEqualTo(adPlaybackStateWithNoAds.adsId);
     assertThat(adPlaybackStateWithNoAdsFromBundle.adGroupCount)
         .isEqualTo(adPlaybackStateWithNoAds.adGroupCount);

libraries/common/src/test/java/androidx/media3/common/MediaItemTest.java

@@ -375,12 +375,18 @@ public void createDefaultClippingConfigurationInstance_checksDefaultValues() {
   }
 
   @Test
-  public void createDefaultClippingConfigurationInstance_roundTripViaBundle_yieldsEqualInstance() {
+  public void
+      createDefaultClippingConfigurationInstance_toBundleSkipsDefaultValues_fromBundleRestoresThem() {
     MediaItem.ClippingConfiguration clippingConfiguration =
         new MediaItem.ClippingConfiguration.Builder().build();
 
+    Bundle clippingConfigurationBundle = clippingConfiguration.toBundle();
+
+    // Check that default values are skipped when bundling.
+    assertThat(clippingConfigurationBundle.keySet()).isEmpty();
+
     MediaItem.ClippingConfiguration clippingConfigurationFromBundle =
-        MediaItem.ClippingConfiguration.CREATOR.fromBundle(clippingConfiguration.toBundle());
+        MediaItem.ClippingConfiguration.CREATOR.fromBundle(clippingConfigurationBundle);
 
     assertThat(clippingConfigurationFromBundle).isEqualTo(clippingConfiguration);
   }
@@ -558,12 +564,18 @@ public void createDefaultLiveConfigurationInstance_checksDefaultValues() {
   }
 
   @Test
-  public void createDefaultLiveConfigurationInstance_roundTripViaBundle_yieldsEqualInstance() {
+  public void
+      createDefaultLiveConfigurationInstance_toBundleSkipsDefaultValues_fromBundleRestoresThem() {
     MediaItem.LiveConfiguration liveConfiguration =
         new MediaItem.LiveConfiguration.Builder().build();
 
+    Bundle liveConfigurationBundle = liveConfiguration.toBundle();
+
+    // Check that default values are skipped when bundling.
+    assertThat(liveConfigurationBundle.keySet()).isEmpty();
+
     MediaItem.LiveConfiguration liveConfigurationFromBundle =
-        MediaItem.LiveConfiguration.CREATOR.fromBundle(liveConfiguration.toBundle());
+        MediaItem.LiveConfiguration.CREATOR.fromBundle(liveConfigurationBundle);
 
     assertThat(liveConfigurationFromBundle).isEqualTo(liveConfiguration);
   }
@@ -832,9 +844,14 @@ public void createDefaultMediaItemInstance_checksDefaultValues() {
   }
 
   @Test
-  public void createDefaultMediaItemInstance_roundTripViaBundle_yieldsEqualInstance() {
+  public void createDefaultMediaItemInstance_toBundleSkipsDefaultValues_fromBundleRestoresThem() {
     MediaItem mediaItem = new MediaItem.Builder().build();
 
+    Bundle mediaItemBundle = mediaItem.toBundle();
+
+    // Check that default values are skipped when bundling.
+    assertThat(mediaItemBundle.keySet()).isEmpty();
+
     MediaItem mediaItemFromBundle = MediaItem.CREATOR.fromBundle(mediaItem.toBundle());
 
     assertThat(mediaItemFromBundle).isEqualTo(mediaItem);

libraries/common/src/test/java/androidx/media3/common/MediaMetadataTest.java

@@ -112,12 +112,11 @@ public void toBundleSkipsDefaultValues_fromBundleRestoresThem() {
 
     Bundle mediaMetadataBundle = mediaMetadata.toBundle();
 
-    // check Bundle created above, contains no keys.
+    // Check that default values are skipped when bundling.
     assertThat(mediaMetadataBundle.keySet()).isEmpty();
 
     MediaMetadata mediaMetadataFromBundle = MediaMetadata.CREATOR.fromBundle(mediaMetadataBundle);
 
-    // check object retrieved from mediaMetadataBundle is equal to mediaMetadata.
     assertThat(mediaMetadataFromBundle).isEqualTo(mediaMetadata);
     // Extras is not implemented in MediaMetadata.equals(Object o).
     assertThat(mediaMetadataFromBundle.extras).isNull();