protocol/contracts/staking/test/utils/number_utils.ts

116 lines
3.5 KiB
TypeScript

import { expect, Numberish } from '@0x/contracts-test-utils';
import { BigNumber } from '@0x/utils';
import { Web3Wrapper } from '@0x/web3-wrapper';
import * as crypto from 'crypto';
import { Decimal } from 'decimal.js';
Decimal.set({ precision: 80 });
/**
* Convert `x` to a `Decimal` type.
*/
export function toDecimal(x: Numberish): Decimal {
if (BigNumber.isBigNumber(x)) {
return new Decimal(x.toString(10));
}
return new Decimal(x);
}
/**
* Generate a random integer between `min` and `max`, inclusive.
*/
export function getRandomInteger(min: Numberish, max: Numberish): BigNumber {
const range = new BigNumber(max).minus(min);
return getRandomPortion(range).plus(min);
}
/**
* Generate a random integer between `0` and `total`, inclusive.
*/
export function getRandomPortion(total: Numberish): BigNumber {
return new BigNumber(total).times(getRandomFloat(0, 1)).integerValue(BigNumber.ROUND_HALF_UP);
}
/**
* Generate a random, high-precision decimal between `min` and `max`, inclusive.
*/
export function getRandomFloat(min: Numberish, max: Numberish): BigNumber {
// Generate a really high precision number between [0, 1]
const r = new BigNumber(crypto.randomBytes(32).toString('hex'), 16).dividedBy(new BigNumber(2).pow(256).minus(1));
return new BigNumber(max)
.minus(min)
.times(r)
.plus(min);
}
export const FIXED_POINT_BASE = new BigNumber(2).pow(127);
/**
* Convert `n` to fixed-point integer represenatation.
*/
export function toFixed(n: Numberish): BigNumber {
return new BigNumber(n).times(FIXED_POINT_BASE).integerValue();
}
/**
* Convert `n` from fixed-point integer represenatation.
*/
export function fromFixed(n: Numberish): BigNumber {
return new BigNumber(n).dividedBy(FIXED_POINT_BASE);
}
/**
* Converts two decimal numbers to integers with `precision` digits, then returns
* the absolute difference.
*/
export function getNumericalDivergence(a: Numberish, b: Numberish, precision: number = 18): number {
const _a = new BigNumber(a);
const _b = new BigNumber(b);
const maxIntegerDigits = Math.max(
_a.integerValue(BigNumber.ROUND_DOWN).sd(true),
_b.integerValue(BigNumber.ROUND_DOWN).sd(true),
);
const _toInteger = (n: BigNumber) => {
const base = 10 ** (precision - maxIntegerDigits);
return n.times(base).integerValue(BigNumber.ROUND_DOWN);
};
return _toInteger(_a)
.minus(_toInteger(_b))
.abs()
.toNumber();
}
/**
* Asserts that two numbers are equal up to `precision` digits.
*/
export function assertRoughlyEquals(actual: Numberish, expected: Numberish, precision: number = 18): void {
if (getNumericalDivergence(actual, expected, precision) <= 1) {
return;
}
expect(actual).to.bignumber.eq(expected);
}
/**
* Asserts that two numbers are equal with up to `maxError` difference between them.
*/
export function assertIntegerRoughlyEquals(actual: Numberish, expected: Numberish, maxError: number = 1): void {
const diff = new BigNumber(actual)
.minus(expected)
.abs()
.toNumber();
if (diff <= maxError) {
return;
}
expect(actual).to.bignumber.eq(expected);
}
/**
* Converts `amount` into a base unit amount with 18 digits.
*/
export function toBaseUnitAmount(amount: Numberish): BigNumber {
const decimals = 18;
const amountAsBigNumber = new BigNumber(amount);
const baseUnitAmount = Web3Wrapper.toBaseUnitAmount(amountAsBigNumber, decimals);
return baseUnitAmount;
}