Due to mission mass limitations, it is not possible to launch both a pressure suit and a space suit for each astronaut. Consequently, NASA is adapting an existing pressure suit called the Modified Advanced Crew Escape Suit (MACES) so that it can also function as a space suit. The astronauts wear the basic pressure suit during launch and landing. For EVA, a Portable Life Support System (PLSS) is attached to the astronaut’s back, and a lightweight thermal management garment is donned over the pressure suit.

Astronauts wearing the MACES will be capable of performing short-duration EVAs that last about four hours. The PLSS is the first new space suit system developed by NASA since the Shuttle Extravehicular Mobility Unit was introduced in 1981. The PLSS uses new several technology components such as a regenerative rapid cycle amine unit for carbon dioxide removal, a suit water membrane evaporator for thermal control, a variable oxygen pressure regulator, and lithium ion batteries for energy storage. The PLSS has been tested with a human metabolic simulator and a mockup space suit, and vacuum chamber tests with a human will begin in 2015.
(From Technology Development For Nasa’s Asteroid Redirect Mission; emphasis mine)

It turns out that Otto Willi Gail provided extensive details for spacesuit testing in his exciting 1929 novel The Shot Into Infinity:

(Spacesuit testing circa 1929)

Korf opened the doors of the chamber built into the wall, entirely finished in rubber and provided with an airtight door.

"Two things (aside from cold which can be overcome) seem to make a stay in space impossible for human beings; the absence of pressure and the lack of air. I'm going to pump the air from this room, which really amounts to nothing more than a laboratory flask on a large scale, so that the interior will be like airless and pressure-less space."

With great excitement the visitors watched Korff take from the drawer a bundle, which he opened up.

"This is a suit made from rubberized leather, like a diving suit, and absolutely airtight. By means of a special air magazine so much air is constantly produced in the suit that there is a constant pressure of one atmosphere, regardless of the external pressure.

Suchinow silently slipped into the costume and allowed Korf to screw on the helmet with the oxygen chambers. Then he placed himself in the center of the chamber. In one of his leather-covered hands Korf placed a burning candle. Then he closed the door, through the glass window of which all the proceedings could be witnessed. They could clearly hear an electric bell in the chamber, which Korf switched on.

The pump began to work. The candle flickered and went out. The bell seemed to sound fainter and fainter, though the clapper kept on striking. korf shut off the pump.

"Now, except for weight and heat, the same conditions prevail in this chamber as in space. Yet Mr. Suchinow, with whom we cannot communicate at present, certainly feels alright."

Sam looked through the window, and laughed out loud. In fact Suchinow presented a very comical appearance. The suit had swelled to its fullest extent and had taken on the shape much like that of the favorite rubber dolls of festival times.
(Read more about Otto Willi Gail's spacesuit testing)

Gail refers to the suits as pneumatic suits; the phrase "space suit" was first used in 1931 by Golden Age scientifiction duo Nat Schachner and Leo Zagat (see space suit from The Emperor of the Stars).