// Source of length 5
    AppendableByteSource source = new AppendableByteSource(newPreFilledByteArray(5));

    // Slice it starting at offset 10.
    ByteSource slice = source.slice(10, 5);

    // Open a stream to the slice.
    InputStream in = slice.openStream();

    // Append 10 more bytes to the source.
    source.append(newPreFilledByteArray(5, 10));

  }

  /** 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++) {

@AndroidIncompatible // Finalization probably just doesn't happen fast enough?
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);
    final File file = out.getFile();
    assertEquals(100, file.length());

    testThreshold(1000, 100, false, false);
  }

  private void testThreshold(
      int fileThreshold, int dataSize, boolean singleByte, boolean resetOnFinalize)
      throws IOException {
    byte[] data = newPreFilledByteArray(dataSize);
    FileBackedOutputStream out = new FileBackedOutputStream(fileThreshold, resetOnFinalize);
    ByteSource source = out.asByteSource();
    int chunk1 = min(dataSize, fileThreshold);

    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);
    assertTrue(Arrays.equals(data, Files.toByteArray(temp)));

    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++) {

    // Source of length 5
    AppendableByteSource source = new AppendableByteSource(newPreFilledByteArray(5));

    // Slice it starting at offset 10.
    ByteSource slice = source.slice(10, 5);

    // Open a stream to the slice.
    InputStream in = slice.openStream();

    // Append 10 more bytes to the source.
    source.append(newPreFilledByteArray(5, 10));

            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;
                          }
                        };

@AndroidIncompatible // Finalization probably just doesn't happen fast enough?
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);
    final File file = out.getFile();
    assertEquals(100, file.length());