message: tests/helpers: add $, $$, createEl, and _
diff: const _ = require('lodash');
  +const { window: { document } } = require('../src/utils/window');
  let counter = 0;
  const helpers = {
  - unique: () => (counter++),
  - uniqueProps: obj => {
  + unique () {
  + return (counter++);
  + },
  +
  + uniqueProps (obj) {
  for (const prop in obj) {
  if (!obj.hasOwnProperty(prop)) { continue; }
  @@ -17,7 +21,7 @@ const helpers = {
  }
  },
  - newCoordsSet: (n = 0) => {
  + newCoordsSet (n = 0) {
  return {
  start: {
  page : { x: n++, y: n++ },
  @@ -37,7 +41,7 @@ const helpers = {
  };
  },
  - newPointer: (n = 50) => {
  + newPointer (n = 50) {
  return {
  pointerId: n++,
  pageX: n++,
  @@ -46,6 +50,20 @@ const helpers = {
  clientY: n++,
  };
  },
  +
  + _,
  +
  + $ (selector, context) {
  + return (context || document).querySelector(selector);
  + },
  +
  + $$ (selector, context) {
  + return Array.from((context || document).querySelectorAll(selector));
  + },
  +
  + createEl (name) {
  + return document.createElement(name);
  + },
  };
  module.exports = helpers;
  