for (BigInteger q : NONZERO_BIGINTEGER_CANDIDATES) {
        for (RoundingMode mode : ALL_SAFE_ROUNDING_MODES) {
          BigInteger expected =
              new BigDecimal(p).divide(new BigDecimal(q), 0, mode).toBigIntegerExact();
          assertEquals(expected, BigIntegerMath.divide(p, q, mode));
        }
      }
    }
  }

  private static final BigInteger BAD_FOR_ANDROID_P = new BigInteger("-9223372036854775808");

  public static BigInteger divide(BigInteger p, BigInteger q, RoundingMode mode) {
    BigDecimal pDec = new BigDecimal(p);
    BigDecimal qDec = new BigDecimal(q);
    return pDec.divide(qDec, 0, mode).toBigIntegerExact();
  }

  /**
   * Returns {@code n!}, that is, the product of the first {@code n} positive integers, or {@code 1}
   * if {@code n == 0}.
   *