return Files.createTempFile(tempDir, "test", ".test");
  }

  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();

   * For example, {@code Splitter.on(Pattern.compile("\r?\n")).split(entireFile)} splits a string
   * into lines whether it uses DOS-style or UNIX-style line terminators.
   *
   * @param separatorPattern the pattern that determines whether a subsequence is a separator. This
   *     pattern may not match the empty string.

   * For example, {@code Splitter.on(Pattern.compile("\r?\n")).split(entireFile)} splits a string
   * into lines whether it uses DOS-style or UNIX-style line terminators.
   *
   * @param separatorPattern the pattern that determines whether a subsequence is a separator. This
   *     pattern may not match the empty string.

  @J2ObjCIncompatible
  public static File createTempDir() {
    return TempFileCreator.INSTANCE.createTempDir();
  }

  /**
   * Creates an empty file or updates the last updated timestamp on the same as the unix command of
   * the same name.
   *
   * @param file the file to create or update
   * @throws IOException if an I/O error occurs
   */
  @SuppressWarnings("GoodTime") // reading system time without TimeSource