assertEquals(3, hashCodes.size());
  }

  public void testToString() {
    assertEquals("Hashing.sipHash24(" + K0 + ", " + K1 + ")", SIP_WITH_KEY.toString());
    assertEquals("Hashing.sipHash24(" + K0 + ", " + K1 + ")", SIP_WITHOUT_KEY.toString());
    assertEquals("Hashing.sipHash24(20, 13)", Hashing.sipHash24(20, 13).toString());
  }

  private static void assertSip(String input, long expected) {

    assertEquals(3, hashCodes.size());
  }

  public void testToString() {
    assertEquals("Hashing.sipHash24(" + K0 + ", " + K1 + ")", SIP_WITH_KEY.toString());
    assertEquals("Hashing.sipHash24(" + K0 + ", " + K1 + ")", SIP_WITHOUT_KEY.toString());
    assertEquals("Hashing.sipHash24(20, 13)", Hashing.sipHash24(20, 13).toString());
  }

  private static void assertSip(String input, long expected) {

    HashTestUtils.check2BitAvalanche(Hashing.sipHash24(), 250, 0.14);
    HashTestUtils.checkAvalanche(Hashing.sipHash24(), 250, 0.10);
    HashTestUtils.checkNo2BitCharacteristics(Hashing.sipHash24());
    HashTestUtils.checkNoFunnels(Hashing.sipHash24());
    HashTestUtils.assertInvariants(Hashing.sipHash24());
    assertEquals(
        "Hashing.sipHash24(506097522914230528, 1084818905618843912)",

   *
   * @since 15.0
   */
  public static HashFunction sipHash24() {
    return SipHashFunction.SIP_HASH_24;
  }

  /**
   * Returns a hash function implementing the <a href="https://131002.net/siphash/">64-bit
   * SipHash-2-4 algorithm</a> using the given seed.
   *
   * @since 15.0
   */
  public static HashFunction sipHash24(long k0, long k1) {
    return new SipHashFunction(2, 4, k0, k1);
  }