ava rewiremock

ava-rewiremock.js

import test from 'ava';
import sinon from 'sinon';

// nothing would be mocked before import
import rewiremock from 'rewiremock/node';
import fs from 'fs';
// ^ only this "FS" would be mocked

rewiremock('fs').mockThrough(() => sinon.stub());
// ^ this line would be "hoisted" 

// here rewiremock would disable itself.

fs.mount('/some/test/directory/', "what you were going to do?");