*
   * @param sources the sources to concatenate
   * @return a {@code ByteSource} containing the concatenated data
   * @since 15.0
   */
  public static ByteSource concat(Iterable<? extends ByteSource> sources) {
    return new ConcatenatedByteSource(sources);
  }

  /**
   * Concatenates multiple {@link ByteSource} instances into a single source. Streams returned from

  public void testConcat() throws IOException {
    ByteSource b1 = ByteSource.wrap(new byte[] {0, 1, 2, 3});
    ByteSource b2 = ByteSource.wrap(new byte[0]);
    ByteSource b3 = ByteSource.wrap(new byte[] {4, 5});

    byte[] expected = {0, 1, 2, 3, 4, 5};

    assertArrayEquals(expected, ByteSource.concat(ImmutableList.of(b1, b2, b3)).read());
    assertArrayEquals(expected, ByteSource.concat(b1, b2, b3).read());

  public void testConcat() throws IOException {
    ByteSource b1 = ByteSource.wrap(new byte[] {0, 1, 2, 3});
    ByteSource b2 = ByteSource.wrap(new byte[0]);
    ByteSource b3 = ByteSource.wrap(new byte[] {4, 5});

    byte[] expected = {0, 1, 2, 3, 4, 5};

    assertArrayEquals(expected, ByteSource.concat(ImmutableList.of(b1, b2, b3)).read());
    assertArrayEquals(expected, ByteSource.concat(b1, b2, b3).read());

    this.state = new State(fileThreshold, resetWhenGarbageCollected);
    this.byteSource = new FbosByteSource(state);

    if (resetWhenGarbageCollected) {
      FinalizableReference.register(byteSource);
    }
  }

  private static final class FinalizableReference extends FinalizablePhantomReference<ByteSource> {
    static final FinalizableReferenceQueue referenceQueue = new FinalizableReferenceQueue();

    @Override
    public void tearDown() throws IOException {}
  }

  private static class ByteArraySourceFactory implements ByteSourceFactory {

    @Override
    public ByteSource createSource(byte[] bytes) throws IOException {
      return ByteSource.wrap(bytes);
    }

    @Override
    public byte[] getExpected(byte[] bytes) {
      return bytes;
    }

    @Override

 * be an empty line at the end if the contents are terminated with a line separator.
 *
 * <p>Any {@link ByteSource} containing text encoded with a specific {@linkplain Charset character
 * encoding} may be viewed as a {@code CharSource} using {@link ByteSource#asCharSource(Charset)}.
 *
 * <p><b>Note:</b> In general, {@code CharSource} is intended to be used for "file-like" sources

  public void testByteSource_size_ofDirectory() throws IOException {
    try (FileSystem fs = Jimfs.newFileSystem(Configuration.unix())) {
      Path dir = fs.getPath("dir");
      Files.createDirectory(dir);

      ByteSource source = MoreFiles.asByteSource(dir);

      assertThat(source.sizeIfKnown()).isAbsent();

      assertThrows(IOException.class, source::size);
    }
  }

    return suite;
  }

  public void testRoundTripSources() throws Exception {
    File asciiFile = getTestFile("ascii.txt");
    ByteSource byteSource = Files.asByteSource(asciiFile);
    assertThat(byteSource.asCharSource(UTF_8).asByteSource(UTF_8)).isSameInstanceAs(byteSource);
  }

  public void testToByteArray() throws IOException {
    File asciiFile = getTestFile("ascii.txt");
    File i18nFile = getTestFile("i18n.txt");

   */
  public static ByteSource asByteSource(Path path, OpenOption... options) {
    return new PathByteSource(path, options);
  }

  @IgnoreJRERequirement // *should* be redundant with the one on MoreFiles itself
  private static final class PathByteSource extends
      ByteSource
  {

    private static final LinkOption[] FOLLOW_LINKS = {};

  public void testByteSource_size_ofDirectory() throws IOException {
    try (FileSystem fs = Jimfs.newFileSystem(Configuration.unix())) {
      Path dir = fs.getPath("dir");
      Files.createDirectory(dir);

      ByteSource source = MoreFiles.asByteSource(dir);

      assertThat(source.sizeIfKnown()).isAbsent();

      assertThrows(IOException.class, source::size);
    }
  }