import test from 'ava' import fs from 'fs' import mock from 'mock-fs' test.before(t => { mock({ 'dir': { 'document': 'mocked content' } }) }); test.after.always(t => { mock.restore() }); test('fs sync', t => { var contents = fs.readFileSync('dir/document', 'utf8') t.is(contents, 'mocked content', 'mocked file content') }); test('fs async', async t => { const testReadFile = new Promise(function(resolve, reject) { fs.readFile('dir/document', 'utf8', (err, data) => { err ? reject(err) : resolve(data); }) }) t.is(await testReadFile, 'mocked content', 'mocked file content') });