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());

  }

  // Test that you can not expand the readable data in a previously sliced ByteSource.
  public void testSlice_constrainedRange() throws IOException {
    long size = source.read().length;
    if (size >= 2) {
      ByteSource sliced = source.slice(1, size - 2);
      assertEquals(size - 2, sliced.read().length);
      ByteSource resliced = sliced.slice(0, size - 1);
      assertTrue(sliced.contentEquals(resliced));
    }

  }

  // Test that you can not expand the readable data in a previously sliced ByteSource.
  public void testSlice_constrainedRange() throws IOException {
    long size = source.read().length;
    if (size >= 2) {
      ByteSource sliced = source.slice(1, size - 2);
      assertEquals(size - 2, sliced.read().length);
      ByteSource resliced = sliced.slice(0, size - 1);
      assertTrue(sliced.contentEquals(resliced));
    }

  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 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);
    }
  }

  /**
   * Returns a {@code ByteSource} that reads base-encoded bytes from the specified {@code
   * CharSource}.
   */
  @J2ktIncompatible
  @GwtIncompatible // ByteSource,CharSource
  public final ByteSource decodingSource(CharSource encodedSource) {
    checkNotNull(encodedSource);
    return new ByteSource() {
      @Override
      public InputStream openStream() throws IOException {

    assertFreshInstanceReturned(
        ByteArrayOutputStream.class, OutputStream.class,
        Writer.class, StringWriter.class,
        PrintStream.class, PrintWriter.class);
    assertEquals(ByteSource.empty(), ArbitraryInstances.get(ByteSource.class));
    assertEquals(CharSource.empty(), ArbitraryInstances.get(CharSource.class));
    assertThat(ArbitraryInstances.get(ByteSink.class)).isNotNull();

    assertFreshInstanceReturned(
        ByteArrayOutputStream.class, OutputStream.class,
        Writer.class, StringWriter.class,
        PrintStream.class, PrintWriter.class);
    assertEquals(ByteSource.empty(), ArbitraryInstances.get(ByteSource.class));
    assertEquals(CharSource.empty(), ArbitraryInstances.get(CharSource.class));
    assertThat(ArbitraryInstances.get(ByteSink.class)).isNotNull();