test('format ordinal', () => {
  assert.equal(moment([2011, 0, 1]).format('DDDo'), '1st', '1st');
  assert.equal(moment([2011, 0, 2]).format('DDDo'), '2nd', '2nd');
  assert.equal(moment([2011, 0, 3]).format('DDDo'), '3rd', '3rd');
  assert.equal(moment([2011, 0, 4]).format('DDDo'), '4th', '4th');