diff --git a/libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerMultiSequenceCompositionTest.java b/libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerMultiSequenceCompositionTest.java
index b5848735c6..b0314831ed 100644
--- a/libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerMultiSequenceCompositionTest.java
+++ b/libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerMultiSequenceCompositionTest.java
@@ -108,7 +108,8 @@ public final class TransformerMultiSequenceCompositionTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     assertBitmapsMatchExpected(
         extractBitmapsFromVideo(context, checkNotNull(result.filePath)), testId);
   }
@@ -142,7 +143,8 @@ public final class TransformerMultiSequenceCompositionTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     assertBitmapsMatchExpected(
         extractBitmapsFromVideo(context, checkNotNull(result.filePath)), testId);
   }
@@ -198,7 +200,8 @@ public final class TransformerMultiSequenceCompositionTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     assertBitmapsMatchExpected(
         extractBitmapsFromVideo(context, checkNotNull(result.filePath)), testId);
   }
diff --git a/libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerSequenceEffectTest.java b/libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerSequenceEffectTest.java
index ae9041b99c..890cefe9e1 100644
--- a/libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerSequenceEffectTest.java
+++ b/libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerSequenceEffectTest.java
@@ -140,7 +140,8 @@ public final class TransformerSequenceEffectTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     assertBitmapsMatchExpectedAndSave(
         extractBitmapsFromVideo(context, checkNotNull(result.filePath)), testId);
   }
@@ -437,7 +438,8 @@ public final class TransformerSequenceEffectTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     assertBitmapsMatchExpectedAndSave(
         extractBitmapsFromVideo(context, checkNotNull(result.filePath)), testId);
   }
@@ -460,7 +462,8 @@ public final class TransformerSequenceEffectTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     assertBitmapsMatchExpectedAndSave(
         extractBitmapsFromVideo(context, checkNotNull(result.filePath)), testId);
   }
@@ -484,7 +487,8 @@ public final class TransformerSequenceEffectTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     assertBitmapsMatchExpectedAndSave(
         extractBitmapsFromVideo(context, checkNotNull(result.filePath)), testId);
   }
@@ -509,7 +513,8 @@ public final class TransformerSequenceEffectTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     assertBitmapsMatchExpectedAndSave(
         extractBitmapsFromVideo(context, checkNotNull(result.filePath)), testId);
   }
@@ -534,7 +539,8 @@ public final class TransformerSequenceEffectTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     assertBitmapsMatchExpectedAndSave(
         extractBitmapsFromVideo(context, checkNotNull(result.filePath)), testId);
   }
diff --git a/libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerUltraHdrTest.java b/libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerUltraHdrTest.java
index da595ab864..fcd72c2776 100644
--- a/libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerUltraHdrTest.java
+++ b/libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerUltraHdrTest.java
@@ -94,7 +94,8 @@ public final class TransformerUltraHdrTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     assertSdrColors(context, result.filePath);
   }
 
@@ -115,7 +116,8 @@ public final class TransformerUltraHdrTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     assertSdrColors(context, result.filePath);
   }
 
@@ -137,7 +139,8 @@ public final class TransformerUltraHdrTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     assertSdrColors(context, result.filePath);
   }
 
@@ -152,7 +155,8 @@ public final class TransformerUltraHdrTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     assertSdrColors(context, result.filePath);
   }
 
@@ -169,7 +173,8 @@ public final class TransformerUltraHdrTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     assertSdrColors(context, result.filePath);
   }
 
diff --git a/libraries/transformer/src/androidTest/java/androidx/media3/transformer/mh/TransformerMhUltraHdrTest.java b/libraries/transformer/src/androidTest/java/androidx/media3/transformer/mh/TransformerMhUltraHdrTest.java
index 712d91df33..6711ec72ee 100644
--- a/libraries/transformer/src/androidTest/java/androidx/media3/transformer/mh/TransformerMhUltraHdrTest.java
+++ b/libraries/transformer/src/androidTest/java/androidx/media3/transformer/mh/TransformerMhUltraHdrTest.java
@@ -83,7 +83,8 @@ public final class TransformerMhUltraHdrTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     ColorInfo colorInfo =
         retrieveTrackFormat(context, result.filePath, C.TRACK_TYPE_VIDEO).colorInfo;
     assertThat(colorInfo.colorSpace).isEqualTo(C.COLOR_SPACE_BT2020);
@@ -104,7 +105,8 @@ public final class TransformerMhUltraHdrTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     ColorInfo colorInfo =
         retrieveTrackFormat(context, result.filePath, C.TRACK_TYPE_VIDEO).colorInfo;
     assertThat(colorInfo.colorSpace).isEqualTo(C.COLOR_SPACE_BT2020);
@@ -125,7 +127,8 @@ public final class TransformerMhUltraHdrTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     ColorInfo colorInfo =
         retrieveTrackFormat(context, result.filePath, C.TRACK_TYPE_VIDEO).colorInfo;
     assertThat(colorInfo.colorSpace).isEqualTo(C.COLOR_SPACE_BT2020);
@@ -146,7 +149,8 @@ public final class TransformerMhUltraHdrTest {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     assertSdrColors(context, result.filePath);
   }
 
diff --git a/libraries/transformer/src/androidTest/java/androidx/media3/transformer/mh/TransformerSequenceEffectTestWithHdr.java b/libraries/transformer/src/androidTest/java/androidx/media3/transformer/mh/TransformerSequenceEffectTestWithHdr.java
index 9fe001c636..6476190cd9 100644
--- a/libraries/transformer/src/androidTest/java/androidx/media3/transformer/mh/TransformerSequenceEffectTestWithHdr.java
+++ b/libraries/transformer/src/androidTest/java/androidx/media3/transformer/mh/TransformerSequenceEffectTestWithHdr.java
@@ -107,7 +107,8 @@ public final class TransformerSequenceEffectTestWithHdr {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     // Expected bitmaps were generated on the Pixel 7 Pro, because emulators don't
     // support decoding HDR.
     assertBitmapsMatchExpectedAndSave(
@@ -185,7 +186,8 @@ public final class TransformerSequenceEffectTestWithHdr {
             .build()
             .run(testId, composition);
 
-    assertThat(result.filePath).isNotNull();
+    assertThat(result.filePath).isNotEmpty();
+    assertThat(result.exportResult.fileSizeBytes).isGreaterThan(0);
     // Expected bitmaps were generated on the Samsung S22 Ultra (US), because emulators don't
     // support decoding HDR, and the Pixel 7 Pro does support HDR editing.
     assertBitmapsMatchExpectedAndSave(