message: test(empty): empty() should equal EMPTY
diff: import marbleTestingSignature = require('../helpers/marble-testing'); // tslint:disable-line:no-require-imports
  import { empty } from '../../src/create';
  +import { EMPTY } from '../../src';
  import { expect } from 'chai';
  declare const asDiagram: any;
  @@ -29,6 +30,10 @@ describe('empty', () => {
  expect(hit).to.be.true;
  });
  + it('should equal EMPTY', () => {
  + expect(empty()).to.equal(EMPTY);
  + });
  +
  it('should take a scheduler', () => {
  const source = empty(rxTestScheduler);
  let hit = false;
  