Add unit tests to FLAC extractor related classes

PiperOrigin-RevId: 287973192

library/core/src/main/java/com/google/android/exoplayer2/extractor/FlacFrameReader.java

@@ -167,7 +167,7 @@ public final class FlacFrameReader {
    * @param data The array to read the data from, whose position must correspond to the block size
    *     bits.
    * @param blockSizeKey The key in the block size lookup table.
-   * @return The block size in samples.
+   * @return The block size in samples, or -1 if the {@code blockSizeKey} is invalid.
    */
   public static int readFrameBlockSizeSamplesFromKey(ParsableByteArray data, int blockSizeKey) {
     switch (blockSizeKey) {

library/core/src/test/java/com/google/android/exoplayer2/util/FlacStreamMetadataTest.java

@@ -17,9 +17,12 @@ package com.google.android.exoplayer2.util;
 
 import static com.google.common.truth.Truth.assertThat;
 
+import androidx.test.core.app.ApplicationProvider;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.android.exoplayer2.metadata.Metadata;
 import com.google.android.exoplayer2.metadata.flac.VorbisComment;
+import com.google.android.exoplayer2.testutil.TestUtil;
+import java.io.IOException;
 import java.util.ArrayList;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -29,6 +32,27 @@ import org.junit.runner.RunWith;
 public final class FlacStreamMetadataTest {
 
   @Test
+  public void constructFromByteArray_setsFieldsCorrectly() throws IOException {
+    byte[] fileData =
+        TestUtil.getByteArray(ApplicationProvider.getApplicationContext(), "flac/bear.flac");
+
+    FlacStreamMetadata streamMetadata =
+        new FlacStreamMetadata(
+            fileData, FlacConstants.STREAM_MARKER_SIZE + FlacConstants.METADATA_BLOCK_HEADER_SIZE);
+
+    assertThat(streamMetadata.minBlockSizeSamples).isEqualTo(4096);
+    assertThat(streamMetadata.maxBlockSizeSamples).isEqualTo(4096);
+    assertThat(streamMetadata.minFrameSize).isEqualTo(445);
+    assertThat(streamMetadata.maxFrameSize).isEqualTo(5776);
+    assertThat(streamMetadata.sampleRate).isEqualTo(48000);
+    assertThat(streamMetadata.sampleRateLookupKey).isEqualTo(10);
+    assertThat(streamMetadata.channels).isEqualTo(2);
+    assertThat(streamMetadata.bitsPerSample).isEqualTo(16);
+    assertThat(streamMetadata.bitsPerSampleLookupKey).isEqualTo(4);
+    assertThat(streamMetadata.totalSamples).isEqualTo(131568);
+  }
+
+  @Test
   public void parseVorbisComments() {
     ArrayList<String> commentsList = new ArrayList<>();
     commentsList.add("Title=Song");