Fix FLAC extension tests

- Add @test annotations.
- Fix seeking to ignore potential placeholders
  (see https://xiph.org/flac/format.html#metadata_block_seektable).

PiperOrigin-RevId: 279074092

extensions/flac/src/androidTest/java/com/google/android/exoplayer2/ext/flac/FlacBinarySearchSeekerTest.java

@@ -25,6 +25,7 @@ import com.google.android.exoplayer2.testutil.FakeExtractorInput;
 import com.google.android.exoplayer2.testutil.TestUtil;
 import java.io.IOException;
 import org.junit.Before;
+import org.junit.Test;
 import org.junit.runner.RunWith;
 
 /** Unit test for {@link FlacBinarySearchSeeker}. */
@@ -41,6 +42,7 @@ public final class FlacBinarySearchSeekerTest {
     }
   }
 
+  @Test
   public void testGetSeekMap_returnsSeekMapWithCorrectDuration()
       throws IOException, FlacDecoderException, InterruptedException {
     byte[] data =
@@ -63,6 +65,7 @@ public final class FlacBinarySearchSeekerTest {
     assertThat(seekMap.isSeekable()).isTrue();
   }
 
+  @Test
   public void testSetSeekTargetUs_returnsSeekPending()
       throws IOException, FlacDecoderException, InterruptedException {
     byte[] data =

extensions/flac/src/androidTest/java/com/google/android/exoplayer2/ext/flac/FlacExtractorSeekTest.java

@@ -41,6 +41,7 @@ import java.io.IOException;
 import java.util.List;
 import java.util.Random;
 import org.junit.Before;
+import org.junit.Test;
 import org.junit.runner.RunWith;
 
 /** Seeking tests for {@link FlacExtractor} when the FLAC stream does not have a SEEKTABLE. */
@@ -76,6 +77,7 @@ public final class FlacExtractorSeekTest {
     positionHolder = new PositionHolder();
   }
 
+  @Test
   public void testFlacExtractorReads_nonSeekTableFile_returnSeekableSeekMap()
       throws IOException, InterruptedException {
     FlacExtractor extractor = new FlacExtractor();
@@ -87,6 +89,7 @@ public final class FlacExtractorSeekTest {
     assertThat(seekMap.isSeekable()).isTrue();
   }
 
+  @Test
   public void testHandlePendingSeek_handlesSeekingToPositionInFile_extractsCorrectFrame()
       throws IOException, InterruptedException {
     FlacExtractor extractor = new FlacExtractor();
@@ -103,6 +106,7 @@ public final class FlacExtractorSeekTest {
         trackOutput, targetSeekTimeUs, extractedFrameIndex);
   }
 
+  @Test
   public void testHandlePendingSeek_handlesSeekToEoF_extractsLastFrame()
       throws IOException, InterruptedException {
     FlacExtractor extractor = new FlacExtractor();
@@ -120,6 +124,7 @@ public final class FlacExtractorSeekTest {
         trackOutput, targetSeekTimeUs, extractedFrameIndex);
   }
 
+  @Test
   public void testHandlePendingSeek_handlesSeekingBackward_extractsCorrectFrame()
       throws IOException, InterruptedException {
     FlacExtractor extractor = new FlacExtractor();
@@ -139,6 +144,7 @@ public final class FlacExtractorSeekTest {
         trackOutput, targetSeekTimeUs, extractedFrameIndex);
   }
 
+  @Test
   public void testHandlePendingSeek_handlesSeekingForward_extractsCorrectFrame()
       throws IOException, InterruptedException {
     FlacExtractor extractor = new FlacExtractor();
@@ -158,6 +164,7 @@ public final class FlacExtractorSeekTest {
         trackOutput, targetSeekTimeUs, extractedFrameIndex);
   }
 
+  @Test
   public void testHandlePendingSeek_handlesRandomSeeks_extractsCorrectFrame()
       throws IOException, InterruptedException {
     FlacExtractor extractor = new FlacExtractor();

extensions/flac/src/androidTest/java/com/google/android/exoplayer2/ext/flac/FlacExtractorTest.java

@@ -21,6 +21,7 @@ import androidx.test.core.app.ApplicationProvider;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.android.exoplayer2.testutil.ExtractorAsserts;
 import org.junit.Before;
+import org.junit.Test;
 import org.junit.runner.RunWith;
 
 /** Unit test for {@link FlacExtractor}. */
@@ -34,11 +35,13 @@ public class FlacExtractorTest {
     }
   }
 
+  @Test
   public void testExtractFlacSample() throws Exception {
     ExtractorAsserts.assertBehavior(
         FlacExtractor::new, "bear.flac", ApplicationProvider.getApplicationContext());
   }
 
+  @Test
   public void testExtractFlacSampleWithId3Header() throws Exception {
     ExtractorAsserts.assertBehavior(
         FlacExtractor::new, "bear_with_id3.flac", ApplicationProvider.getApplicationContext());

extensions/flac/src/main/jni/flac_parser.cc

@@ -456,6 +456,9 @@ bool FLACParser::getSeekPositions(int64_t timeUs,
 
   for (unsigned i = length; i != 0; i--) {
     int64_t sampleNumber = points[i - 1].sample_number;
+    if (sampleNumber == -1) {  // placeholder
+      continue;
+    }
     if (sampleNumber <= targetSampleNumber) {
       result[0] = (sampleNumber * 1000000LL) / sampleRate;
       result[1] = firstFrameOffset + points[i - 1].stream_offset;