}

  public void testFactorialNegative() {
    assertThrows(IllegalArgumentException.class, () -> BigIntegerMath.factorial(-1));
  }

  public void testBinomialSmall() {
    runBinomialTest(0, 30);
  }

  @GwtIncompatible // too slow
  public void testBinomialLarge() {
    runBinomialTest(31, 100);
  }