async-await.js

// as a test function callback
it('removes username', inject([Storage], async storage => {
  await storage.set('username', 'test user');
  await storage.clear();
  expect(await storage.get('username').toBeNull();
}));

promises.js

/* Promise chain Version */
it('removes username', inject([Storage], storage => {
  // return needs to be used here to return the Promise chain to
  // `it` so it handles asynchronicity. Remember that `async`
  // is already returning a Promise
  return storage.set('username', 'test user')
  .then(() => storage.clear())
  .then(() => storage.get('username'))
  .then(username => expect(username).toBeNull())
});