}
    }
  }

  public void testFactorial() {
    BigInteger expected = BigInteger.ONE;
    for (int i = 1; i <= 200; i++) {
      expected = expected.multiply(BigInteger.valueOf(i));
      assertEquals(expected, BigIntegerMath.factorial(i));
    }
  }

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