FileBackedOutputStream out = new FileBackedOutputStream(/* fileThreshold= */ 10);
    ByteSource source = out.asByteSource();

    byte[] chunk1 = newPreFilledByteArray(8); // Below threshold
    byte[] chunk2 = newPreFilledByteArray(5); // Crosses threshold
    byte[] chunk3 = newPreFilledByteArray(20); // More data to file

    out.write(chunk1);
    assertThat(out.getFile()).isNull();

    out.write(chunk2);

    FileBackedOutputStream out = new FileBackedOutputStream(/* fileThreshold= */ 10);
    ByteSource source = out.asByteSource();

    byte[] chunk1 = newPreFilledByteArray(8); // Below threshold
    byte[] chunk2 = newPreFilledByteArray(5); // Crosses threshold
    byte[] chunk3 = newPreFilledByteArray(20); // More data to file

    out.write(chunk1);
    assertThat(out.getFile()).isNull();

    out.write(chunk2);

    Files.write(I18N, temp, UTF_16LE);
    assertEquals(I18N, Files.toString(temp, UTF_16LE));
  }

  public void testWriteBytes() throws IOException {
    File temp = createTempFile();
    byte[] data = newPreFilledByteArray(2000);
    Files.write(data, temp);
    assertThat(Files.toByteArray(temp)).isEqualTo(data);

    assertThrows(NullPointerException.class, () -> Files.write(null, temp));
  }

  }

  /** Returns a byte array of length size that has values 0 .. size - 1. */
  static byte[] newPreFilledByteArray(int size) {
    return newPreFilledByteArray(0, size);
  }

  /** Returns a byte array of length size that has values offset .. offset + size - 1. */
  static byte[] newPreFilledByteArray(int offset, int size) {
    byte[] array = new byte[size];
    for (int i = 0; i < size; i++) {

            Collections.singleton(
                    new ByteSource() {
                      @Override
                      public InputStream openStream() {
                        return new ByteArrayInputStream(newPreFilledByteArray(0, 50)) {
                          @Override
                          public long skip(long n) {
                            return 0;
                          }
                        };

            Collections.singleton(
                    new ByteSource() {
                      @Override
                      public InputStream openStream() {
                        return new ByteArrayInputStream(newPreFilledByteArray(0, 50)) {
                          @Override
                          public long skip(long n) {
                            return 0;
                          }
                        };

@NullUnmarked
public class FileBackedOutputStreamAndroidIncompatibleTest extends IoTestCase {

  public void testFinalizeDeletesFile() throws Exception {
    byte[] data = newPreFilledByteArray(100);
    FileBackedOutputStream out = new FileBackedOutputStream(0, true);

    write(out, data, 0, 100, true);
    File file = out.getFile();
    assertEquals(100, file.length());
    assertTrue(file.exists());

    Files.write(I18N, temp, UTF_16LE);
    assertEquals(I18N, Files.toString(temp, UTF_16LE));
  }

  public void testWriteBytes() throws IOException {
    File temp = createTempFile();
    byte[] data = newPreFilledByteArray(2000);
    Files.write(data, temp);
    assertThat(Files.toByteArray(temp)).isEqualTo(data);

    assertThrows(NullPointerException.class, () -> Files.write(null, temp));
  }

/**
 * Tests for the default implementations of {@code ByteSink} methods.
 *
 * @author Colin Decker
 */
@NullUnmarked
public class ByteSinkTest extends IoTestCase {

  private final byte[] bytes = newPreFilledByteArray(10000);

  private TestByteSink sink;

  @Override
  protected void setUp() throws Exception {
    sink = new TestByteSink();
  }

  public void testOpenBufferedStream() throws IOException {