}

  @Override
  public void setUp() throws IOException {
    source = factory.createSource(data);
  }

  public void testOpenStream() throws IOException {
    InputStream in = source.openStream();
    try {
      byte[] readBytes = ByteStreams.toByteArray(in);
      assertExpectedBytes(readBytes);
    } finally {
      in.close();
    }
  }

    // 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));

    // The stream reports no bytes... importantly, it doesn't read the byte at index 5 when it

    }
  }

  private static final class NullByteSink extends ByteSink implements Serializable {
    private static final NullByteSink INSTANCE = new NullByteSink();

    @Override
    public OutputStream openStream() {
      return ByteStreams.nullOutputStream();
    }
  }

  // Compare by toString() to satisfy 2 properties:
  // 1. compareTo(null) should throw NullPointerException

    // read the first 8 chars manually, since there's no equivalent to ByteSource.slice
    // TODO(cgdecker): Add CharSource.slice?
    StringBuilder builder = new StringBuilder();
    Reader reader = concatenated.openStream(); // no need to worry about closing
    for (int i = 0; i < 8; i++) {
      builder.append((char) reader.read());
    }
    assertEquals(expected, builder.toString());
  }

    for (int i = 0; i < size; i++) {
      array[i] = (byte) (offset + i);
    }
    return array;
  }

  private static void copy(URL url, File file) throws IOException {
    InputStream in = url.openStream();
    try {
      OutputStream out = new FileOutputStream(file);
      try {
        byte[] buf = new byte[4096];
        for (int read = in.read(buf); read != -1; read = in.read(buf)) {