nester-promises.js

var before = client.stats().then(function(beforeStats) { return beforeStats } );
var put = before.then(function() { return client.put('k', 'v'); });
var after = put.then(function() { return client.stats(); });
Promise.all([before, after]).then(function(results) {
  // results is an array of 2 elements, with the stats before and stats after
  expect(results[1].stores).toBe(results[0].stores + 1);
});