Ignore decoding test cases when library not available

#minor-release

PiperOrigin-RevId: 452043577

extensions/opus/src/test/java/com/google/android/exoplayer2/ext/opus/OpusDecoderTest.java

@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.ext.opus;
 
 import static com.google.common.truth.Truth.assertThat;
+import static org.junit.Assume.assumeTrue;
 
 import androidx.annotation.Nullable;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
@@ -26,7 +27,6 @@
 import com.google.common.collect.ImmutableList;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
-import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -69,11 +69,6 @@ protected void loadLibrary(String name) {
   private static final ImmutableList<byte[]> FULL_INITIALIZATION_DATA =
       ImmutableList.of(HEADER, CUSTOM_PRE_SKIP_BYTES, CUSTOM_SEEK_PRE_ROLL_BYTES);
 
-  @Before
-  public void setUp() {
-    assertThat(LOADER.isAvailable()).isTrue();
-  }
-
   @Test
   public void getChannelCount() {
     int channelCount = OpusDecoder.getChannelCount(HEADER);
@@ -120,6 +115,7 @@ public void getDiscardPaddingSamples_negativeSampleLength_returnZero() {
 
   @Test
   public void decode_removesPreSkipFromOutput() throws OpusDecoderException {
+    assumeTrue(LOADER.isAvailable());
     OpusDecoder decoder =
         new OpusDecoder(
             /* numInputBuffers= */ 0,
@@ -139,6 +135,7 @@ public void decode_removesPreSkipFromOutput() throws OpusDecoderException {
   @Test
   public void decode_whenDiscardPaddingDisabled_returnsDiscardPadding()
       throws OpusDecoderException {
+    assumeTrue(LOADER.isAvailable());
     OpusDecoder decoder =
         new OpusDecoder(
             /* numInputBuffers= */ 0,
@@ -159,6 +156,7 @@ public void decode_whenDiscardPaddingDisabled_returnsDiscardPadding()
 
   @Test
   public void decode_whenDiscardPaddingEnabled_removesDiscardPadding() throws OpusDecoderException {
+    assumeTrue(LOADER.isAvailable());
     OpusDecoder decoder =
         new OpusDecoder(
             /* numInputBuffers= */ 0,