Using & testing coroutines in Node.js with co & tape

coroutines.js

const bluebird = require('bluebird');
const co = require('co');
const fs = bluebird.promisifyAll(require('fs'));
const _ = require('lodash');

function lsPromise() {
	return co(function* () {
		let paths = { current: '.', root: '/' };
		return yield _.mapValues(paths, path => fs.readdirAsync(path));
	});
}

function lsCallback(cb) {
	cb = cb || () => {};
	return lsPromise()
		.then(files => cb(null, files))
		.catch(e => cb(e));
}

co(function* main() {
	let files = yield lsPromise();
	console.log('promise', files);
});

lsCallback((e, r) => {
	if (e)
		return console.log('error', e);
	console.log('callback', r);
})

package.json

{
  "name": "coroutines",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "engines": {
    "node": ">=4"
  },
  "scripts": {
    "start": "node --use_strict index",
    "test": "node test"
  },
  "author": "nimbus154",
  "license": "MIT",
  "dependencies": {
    "bluebird": "^3.2.2",
    "co": "^4.6.0",
    "lodash": "^4.2.1"
  },
  "devDependencies": {
    "blue-tape": "^0.2.0"
  }
}

test.js

const bluebird = require('bluebird');
const test = require('blue-tape');
const co = require('co');
const fs = bluebird.promisifyAll(require('fs'));

function ls(path) {
	return co(function* () {
		return yield fs.readdirAsync(path);
	});
}

test('should exist', assert => {
	return ls('.');
});

test('not exist', assert => {
	return assert.shouldFail(ls('./not-a-directory'));
});