* @throws IllegalArgumentException if {@code radix} is not between {@link Character#MIN_RADIX}
   *     and {@link Character#MAX_RADIX}.
   */
  public static String toString(long x, int radix) {
    checkArgument(
        radix >= Character.MIN_RADIX && radix <= Character.MAX_RADIX,
        "radix (%s) must be between Character.MIN_RADIX and Character.MAX_RADIX",
        radix);
    if (x == 0) {
      // Simply return "0"

  }

  public void testParseLongThrowsExceptionForInvalidRadix() {
    // Valid radix values are Character.MIN_RADIX to Character.MAX_RADIX, inclusive.
    assertThrows(
        NumberFormatException.class,
        () -> UnsignedLongs.parseUnsignedLong("0", Character.MIN_RADIX - 1));

    assertThrows(
        NumberFormatException.class,

  private static void tryParseAndAssertEquals(Integer expected, String value) {
    assertThat(Ints.tryParse(value)).isEqualTo(expected);
  }

  public void testTryParse_radix() {
    for (int radix = Character.MIN_RADIX; radix <= Character.MAX_RADIX; radix++) {
      radixEncodeParseAndAssertEquals(0, radix);
      radixEncodeParseAndAssertEquals(8000, radix);
      radixEncodeParseAndAssertEquals(-8000, radix);

   *
   * @param string the string containing the unsigned integer representation to be parsed.
   * @param radix the radix to use while parsing {@code s}; must be between {@link
   *     Character#MIN_RADIX} and {@link Character#MAX_RADIX}.
   * @throws NumberFormatException if the string does not contain a valid unsigned {@code int}, or
   *     if supplied radix is invalid.

   * @throws IllegalArgumentException if {@code radix < Character.MIN_RADIX} or {@code radix >
   *     Character.MAX_RADIX}
   * @throws NullPointerException if {@code string} is {@code null}
   * @since 19.0
   */
  public static @Nullable Long tryParse(String string, int radix) {
    if (checkNotNull(string).isEmpty()) {
      return null;
    }
    if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX) {

   */
  private static void tryParseAndAssertEquals(Long expected, String value) {
    assertThat(Longs.tryParse(value)).isEqualTo(expected);
  }

  public void testTryParse_radix() {
    for (int radix = Character.MIN_RADIX; radix <= Character.MAX_RADIX; radix++) {
      radixEncodeParseAndAssertEquals(0L, radix);
      radixEncodeParseAndAssertEquals(8000L, radix);
      radixEncodeParseAndAssertEquals(-8000L, radix);

  private static void tryParseAndAssertEquals(Integer expected, String value) {
    assertThat(Ints.tryParse(value)).isEqualTo(expected);
  }

  public void testTryParse_radix() {
    for (int radix = Character.MIN_RADIX; radix <= Character.MAX_RADIX; radix++) {
      radixEncodeParseAndAssertEquals(0, radix);
      radixEncodeParseAndAssertEquals(8000, radix);
      radixEncodeParseAndAssertEquals(-8000, radix);

   *     {@code string} has a length of zero or cannot be parsed as an integer value
   * @throws IllegalArgumentException if {@code radix < Character.MIN_RADIX} or {@code radix >
   *     Character.MAX_RADIX}
   * @throws NullPointerException if {@code string} is {@code null}
   * @since 19.0
   */
  public static @Nullable Integer tryParse(String string, int radix) {