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Signed SafeMath (#1559)

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* signed safe math

* fix lint errors

* refactor overflow checks and add descriptions

* remove incorrect description

* add test for reversed arguments in multiplication test

* fix power operator

* improve multiplication test descriptions

* Update SafeMath.test.js

* add feature to changelog
This commit is contained in:
Francisco Giordano
2018-12-18 15:54:44 -03:00
committed by GitHub
parent fad30c3d2c
commit d17ae0b806
5 changed files with 325 additions and 121 deletions
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352
test/math/SafeMath.test.js
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@ -1,5 +1,5 @@
const shouldFail = require('../helpers/shouldFail');
const { MAX_UINT256 } = require('../helpers/constants');
const { MAX_UINT256, MIN_INT256, MAX_INT256 } = require('../helpers/constants');
const SafeMathMock = artifacts.require('SafeMathMock');
@ -10,134 +10,264 @@ contract('SafeMath', function () {
this.safeMath = await SafeMathMock.new();
});
describe('add', function () {
it('adds correctly', async function () {
const a = new BigNumber(5678);
const b = new BigNumber(1234);
describe('unsigned', function () {
describe('add', function () {
it('adds correctly', async function () {
const a = new BigNumber(5678);
const b = new BigNumber(1234);
(await this.safeMath.add(a, b)).should.be.bignumber.equal(a.plus(b));
});
it('throws a revert error on addition overflow', async function () {
const a = MAX_UINT256;
const b = new BigNumber(1);
await shouldFail.reverting(this.safeMath.add(a, b));
});
});
describe('sub', function () {
it('subtracts correctly', async function () {
const a = new BigNumber(5678);
const b = new BigNumber(1234);
(await this.safeMath.sub(a, b)).should.be.bignumber.equal(a.minus(b));
});
it('throws a revert error if subtraction result would be negative', async function () {
const a = new BigNumber(1234);
const b = new BigNumber(5678);
await shouldFail.reverting(this.safeMath.sub(a, b));
});
});
describe('mul', function () {
it('multiplies correctly', async function () {
const a = new BigNumber(1234);
const b = new BigNumber(5678);
(await this.safeMath.mul(a, b)).should.be.bignumber.equal(a.times(b));
});
it('handles a zero product correctly (first number as zero)', async function () {
const a = new BigNumber(0);
const b = new BigNumber(5678);
(await this.safeMath.mul(a, b)).should.be.bignumber.equal(a.times(b));
});
it('handles a zero product correctly (second number as zero)', async function () {
const a = new BigNumber(5678);
const b = new BigNumber(0);
(await this.safeMath.mul(a, b)).should.be.bignumber.equal(a.times(b));
});
it('throws a revert error on multiplication overflow', async function () {
const a = MAX_UINT256;
const b = new BigNumber(2);
await shouldFail.reverting(this.safeMath.mul(a, b));
});
});
describe('div', function () {
it('divides correctly', async function () {
const a = new BigNumber(5678);
const b = new BigNumber(5678);
(await this.safeMath.div(a, b)).should.be.bignumber.equal(a.div(b));
});
it('divides zero correctly', async function () {
const a = new BigNumber(0);
const b = new BigNumber(5678);
(await this.safeMath.div(a, b)).should.be.bignumber.equal(0);
});
it('returns complete number result on non-even division', async function () {
const a = new BigNumber(7000);
const b = new BigNumber(5678);
(await this.safeMath.div(a, b)).should.be.bignumber.equal(1);
});
it('throws a revert error on zero division', async function () {
const a = new BigNumber(5678);
const b = new BigNumber(0);
await shouldFail.reverting(this.safeMath.div(a, b));
});
});
describe('mod', function () {
describe('modulos correctly', async function () {
it('when the dividend is smaller than the divisor', async function () {
const a = new BigNumber(284);
const b = new BigNumber(5678);
(await this.safeMath.mod(a, b)).should.be.bignumber.equal(a.mod(b));
(await this.safeMath.addUints(a, b)).should.be.bignumber.equal(a.plus(b));
});
it('when the dividend is equal to the divisor', async function () {
it('reverts on addition overflow', async function () {
const a = MAX_UINT256;
const b = new BigNumber(1);
await shouldFail.reverting(this.safeMath.addUints(a, b));
});
});
describe('sub', function () {
it('subtracts correctly', async function () {
const a = new BigNumber(5678);
const b = new BigNumber(1234);
(await this.safeMath.subUints(a, b)).should.be.bignumber.equal(a.minus(b));
});
it('reverts if subtraction result would be negative', async function () {
const a = new BigNumber(1234);
const b = new BigNumber(5678);
await shouldFail.reverting(this.safeMath.subUints(a, b));
});
});
describe('mul', function () {
it('multiplies correctly', async function () {
const a = new BigNumber(1234);
const b = new BigNumber(5678);
(await this.safeMath.mulUints(a, b)).should.be.bignumber.equal(a.times(b));
});
it('handles a zero product correctly (first number as zero)', async function () {
const a = new BigNumber(0);
const b = new BigNumber(5678);
(await this.safeMath.mulUints(a, b)).should.be.bignumber.equal(a.times(b));
});
it('handles a zero product correctly (second number as zero)', async function () {
const a = new BigNumber(5678);
const b = new BigNumber(0);
(await this.safeMath.mulUints(a, b)).should.be.bignumber.equal(a.times(b));
});
it('reverts on multiplication overflow', async function () {
const a = MAX_UINT256;
const b = new BigNumber(2);
await shouldFail.reverting(this.safeMath.mulUints(a, b));
});
});
describe('div', function () {
it('divides correctly', async function () {
const a = new BigNumber(5678);
const b = new BigNumber(5678);
(await this.safeMath.mod(a, b)).should.be.bignumber.equal(a.mod(b));
(await this.safeMath.divUints(a, b)).should.be.bignumber.equal(a.div(b));
});
it('when the dividend is larger than the divisor', async function () {
it('divides zero correctly', async function () {
const a = new BigNumber(0);
const b = new BigNumber(5678);
(await this.safeMath.divUints(a, b)).should.be.bignumber.equal(0);
});
it('returns complete number result on non-even division', async function () {
const a = new BigNumber(7000);
const b = new BigNumber(5678);
(await this.safeMath.mod(a, b)).should.be.bignumber.equal(a.mod(b));
(await this.safeMath.divUints(a, b)).should.be.bignumber.equal(1);
});
it('when the dividend is a multiple of the divisor', async function () {
const a = new BigNumber(17034); // 17034 == 5678 * 3
const b = new BigNumber(5678);
it('reverts on zero division', async function () {
const a = new BigNumber(5678);
const b = new BigNumber(0);
(await this.safeMath.mod(a, b)).should.be.bignumber.equal(a.mod(b));
await shouldFail.reverting(this.safeMath.divUints(a, b));
});
});
it('reverts with a 0 divisor', async function () {
const a = new BigNumber(5678);
const b = new BigNumber(0);
describe('mod', function () {
describe('modulos correctly', async function () {
it('when the dividend is smaller than the divisor', async function () {
const a = new BigNumber(284);
const b = new BigNumber(5678);
await shouldFail.reverting(this.safeMath.mod(a, b));
(await this.safeMath.modUints(a, b)).should.be.bignumber.equal(a.mod(b));
});
it('when the dividend is equal to the divisor', async function () {
const a = new BigNumber(5678);
const b = new BigNumber(5678);
(await this.safeMath.modUints(a, b)).should.be.bignumber.equal(a.mod(b));
});
it('when the dividend is larger than the divisor', async function () {
const a = new BigNumber(7000);
const b = new BigNumber(5678);
(await this.safeMath.modUints(a, b)).should.be.bignumber.equal(a.mod(b));
});
it('when the dividend is a multiple of the divisor', async function () {
const a = new BigNumber(17034); // 17034 == 5678 * 3
const b = new BigNumber(5678);
(await this.safeMath.modUints(a, b)).should.be.bignumber.equal(a.mod(b));
});
});
it('reverts with a 0 divisor', async function () {
const a = new BigNumber(5678);
const b = new BigNumber(0);
await shouldFail.reverting(this.safeMath.modUints(a, b));
});
});
});
describe('signed', function () {
describe('add', function () {
it('adds correctly if it does not overflow and the result is positve', async function () {
const a = new BigNumber(1234);
const b = new BigNumber(5678);
(await this.safeMath.addUints(a, b)).should.be.bignumber.equal(a.plus(b));
});
it('adds correctly if it does not overflow and the result is negative', async function () {
const a = MAX_INT256;
const b = MIN_INT256;
const result = await this.safeMath.addInts(a, b);
result.should.be.bignumber.equal(a.plus(b));
});
it('reverts on positive addition overflow', async function () {
const a = MAX_INT256;
const b = new BigNumber(1);
await shouldFail.reverting(this.safeMath.addInts(a, b));
});
it('reverts on negative addition overflow', async function () {
const a = MIN_INT256;
const b = new BigNumber(-1);
await shouldFail.reverting(this.safeMath.addInts(a, b));
});
});
describe('sub', function () {
it('subtracts correctly if it does not overflow and the result is positive', async function () {
const a = new BigNumber(5678);
const b = new BigNumber(1234);
const result = await this.safeMath.subInts(a, b);
result.should.be.bignumber.equal(a.minus(b));
});
it('subtracts correctly if it does not overflow and the result is negative', async function () {
const a = new BigNumber(1234);
const b = new BigNumber(5678);
const result = await this.safeMath.subInts(a, b);
result.should.be.bignumber.equal(a.minus(b));
});
it('reverts on positive subtraction overflow', async function () {
const a = MAX_INT256;
const b = new BigNumber(-1);
await shouldFail.reverting(this.safeMath.subInts(a, b));
});
it('reverts on negative subtraction overflow', async function () {
const a = MIN_INT256;
const b = new BigNumber(1);
await shouldFail.reverting(this.safeMath.subInts(a, b));
});
});
describe('mul', function () {
it('multiplies correctly', async function () {
const a = new BigNumber(5678);
const b = new BigNumber(-1234);
const result = await this.safeMath.mulInts(a, b);
result.should.be.bignumber.equal(a.times(b));
});
it('handles a zero product correctly', async function () {
const a = new BigNumber(0);
const b = new BigNumber(5678);
const result = await this.safeMath.mulInts(a, b);
result.should.be.bignumber.equal(a.times(b));
});
it('reverts on multiplication overflow, positive operands', async function () {
const a = MAX_INT256;
const b = new BigNumber(2);
await shouldFail.reverting(this.safeMath.mulInts(a, b));
});
it('reverts when minimum integer is multiplied by -1', async function () {
const a = MIN_INT256;
const b = new BigNumber(-1);
await shouldFail.reverting(this.safeMath.mulInts(a, b));
});
it('reverts when -1 is multiplied by minimum integer', async function () {
const a = new BigNumber(-1);
const b = MIN_INT256;
await shouldFail.reverting(this.safeMath.mulInts(a, b));
});
});
describe('div', function () {
it('divides correctly', async function () {
const a = new BigNumber(-5678);
const b = new BigNumber(5678);
const result = await this.safeMath.divInts(a, b);
result.should.be.bignumber.equal(a.div(b));
});
it('reverts on zero division', async function () {
const a = new BigNumber(-5678);
const b = new BigNumber(0);
await shouldFail.reverting(this.safeMath.divInts(a, b));
});
it('reverts on overflow, negative second', async function () {
const a = new BigNumber(MIN_INT256);
const b = new BigNumber(-1);
await shouldFail.reverting(this.safeMath.divInts(a, b));
});
});
});
});