openzeppelin-contracts/test/SafeMath.js

const assertJump = require('./helpers/assertJump');

contract('SafeMath', function(accounts) {

  let safeMath;

  before(async function() {
    safeMath = await SafeMathMock.new();
  });

  it("multiplies correctly", async function() {
    let a = 5678;
    let b = 1234;
    let mult = await safeMath.multiply(a, b);
    let result = await safeMath.result();
    assert.equal(result, a*b);
  });

  it("adds correctly", async function() {
    let a = 5678;
    let b = 1234;
    let add = await safeMath.add(a, b);
    let result = await safeMath.result();

    assert.equal(result, a+b);
  });

  it("subtracts correctly", async function() {
    let a = 5678;
    let b = 1234;
    let subtract = await safeMath.subtract(a, b);
    let result = await safeMath.result();

    assert.equal(result, a-b);
  });

  it("should throw an error if subtraction result would be negative", async function () {
    let a = 1234;
    let b = 5678;
    try {
      let subtract = await safeMath.subtract(a, b);
    } catch(error) {
      return assertJump(error);
    }
    assert.fail('should have thrown before');
  });

  it("should throw an error on addition overflow", async function() {
    let a = 115792089237316195423570985008687907853269984665640564039457584007913129639935;
    let b = 1;
    try {
      let add = await safeMath.add(a, b);
    } catch(error) {
      return assertJump(error);
    }
    assert.fail('should have thrown before');
  });

  it("should throw an error on multiplication overflow", async function() {
    let a = 115792089237316195423570985008687907853269984665640564039457584007913129639933;
    let b = 2;
    try {
      let multiply = await safeMath.multiply(a, b);
    } catch(error) {
      return assertJump(error);
    }
    assert.fail('should have thrown before');
  });

});