ByteStreams.readFully(newTestStream(10), b, 0, 10);
    assertThat(b).isEqualTo(newPreFilledByteArray(10));

    Arrays.fill(b, (byte) 0);
    ByteStreams.readFully(newTestStream(10), b, 0, 5);
    assertThat(b).isEqualTo(new byte[] {0, 1, 2, 3, 4, 0, 0, 0, 0, 0});
  }

  public void testSkipFully() throws IOException {
    byte[] bytes = newPreFilledByteArray(100);
    skipHelper(0, 0, new ByteArrayInputStream(bytes));

    ByteStreams.readFully(newTestStream(10), b, 0, 10);
    assertThat(b).isEqualTo(newPreFilledByteArray(10));

    Arrays.fill(b, (byte) 0);
    ByteStreams.readFully(newTestStream(10), b, 0, 5);
    assertThat(b).isEqualTo(new byte[] {0, 1, 2, 3, 4, 0, 0, 0, 0, 0});
  }

  public void testSkipFully() throws IOException {
    byte[] bytes = newPreFilledByteArray(100);
    skipHelper(0, 0, new ByteArrayInputStream(bytes));

    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 = Math.min(dataSize, fileThreshold);

  }

  /** 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++) {

    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 = Math.min(dataSize, fileThreshold);

    // 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++) {

    // 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;
                          }
                        };