@Override
  public boolean wasStreamClosed() {
    return byteSink.wasStreamClosed();
  }

  @Override
  public Writer openStream() throws IOException {
    // using TestByteSink's output stream to get option behavior, so flush to it on every write
    return new FilterWriter(new OutputStreamWriter(byteSink.openStream(), UTF_8)) {
      @Override
      public void write(int c) throws IOException {
        super.write(c);
        flush();

  }

  /** A byte source that reads from a URL using {@link URL#openStream()}. */
  private static final class UrlByteSource extends ByteSource {

    private final URL url;

    private UrlByteSource(URL url) {
      this.url = checkNotNull(url);
    }

    @Override
    public InputStream openStream() throws IOException {
      return url.openStream();
    }

    @Override
    public String toString() {

      @Override
      String read(ByteSource byteSource, Charset cs) throws IOException {
        StringBuilder sb = new StringBuilder();
        try (InputStreamReader reader = new InputStreamReader(byteSource.openStream(), cs)) {
          CharStreams.copy(reader, sb);
        }
        return sb.toString();
      }
    },
    // It really seems like this should be faster than TO_BYTE_ARRAY_NEW_STRING.  But it just isn't

        final URL classURL = ResourceUtil.getResource(classFilePath);
        final URL jarURL = new File(JarFileUtil.toJarFilePath(classURL)).toURI().toURL();
        ResourceTraversalUtil.forEach(new ZipInputStream(jarURL.openStream()), (ResourceHandler) (path, is) -> {
            try {
                if (count < 10) {
                    System.out.println(path);
                }
                assertThat(path, is(notNullValue()));

        final URL classURL = ResourceUtil.getResource(classFilePath);
        final URL jarURL = new File(JarFileUtil.toJarFilePath(classURL)).toURI().toURL();
        ClassTraversalUtil.forEach(new ZipInputStream(jarURL.openStream()), (ClassHandler) (packageName, shortClassName) -> {
            if (count < 10) {
                System.out.println(ClassUtil.concatName(packageName, shortClassName));
            }

    advance();
  }

  /** Closes the current reader and opens the next one, if any. */
  private void advance() throws IOException {
    close();
    if (it.hasNext()) {
      current = it.next().openStream();
    }
  }

  @Override
  public int read(char[] cbuf, int off, int len) throws IOException {
    checkNotNull(cbuf);
    if (current == null) {
      return -1;
    }

  public boolean wasStreamOpened() {
    return outputStreamOpened;
  }

  @Override
  public boolean wasStreamClosed() {
    return outputStreamClosed;
  }

  @Override
  public OutputStream openStream() throws IOException {
    outputStreamOpened = true;
    bytes.reset(); // truncate
    return new Out();
  }

  private final class Out extends TestOutputStream {

    Out() throws IOException {

    public static InputStream getResourceAsStream(final String path, final String extension) {
        assertArgumentNotEmpty("path", path);

        final URL url = getResource(path, extension);
        return URLUtil.openStream(url);
    }

    /**
     * Returns the resource as a stream from the context class loader.
     * Returns <code>null</code> if the resource is not found.
     *
     * @param path

     */
    public static int copy(final URL in, final OutputStream out) {
        assertArgumentNotNull("in", in);
        assertArgumentNotNull("out", out);

        final InputStream is = URLUtil.openStream(in);
        try {
            if (out instanceof FileOutputStream) {
                return copyInternal(wrap(is), (FileOutputStream) out);
            }
            return copyInternal(wrap(is), wrap(out));

     *
     * @return a new input stream positioned at the start of the content
     * @throws IOException if the stream cannot be created or opened
     */
    @Nonnull
    InputStream openStream() throws IOException;

    /**
     * Returns a human-readable description of where this source came from,
     * used primarily for error messages and debugging.
     * <p>
     * Examples of locations:
     * <ul>