assertEquals(expected, BigIntegerMath.factorial(i));
    }
  }

  public void testFactorial0() {
    assertEquals(BigInteger.ONE, BigIntegerMath.factorial(0));
  }

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

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

  @GwtIncompatible // too slow