testEncodeDecode(
      a1000MaxCodePoint,
      "xn--$a1000-nc89312g",
    )
    assertNull(
      Punycode.encode(a1000MaxCodePoint.repeat(2)),
    )
  }

  @Test fun invalidPunycode() {
    assertNull(Punycode.decode("xn--ls8h="))
  }

  private fun testEncodeDecode(
    unicode: String,
    punycode: String,
  ) {
    assertEquals(unicode, Punycode.decode(punycode))