Calabasas-based National Technical Systems, which provides test and engineering services, said this morning that it has acquired Garwood Laboratories, a Southern California provider of product certification labs. Financial terms of the buy were not announced. Garwood has facilities in Pico Rivera and San Clemente, and services the commercial, defense, space, medical, aviation and transportation industries. NTS said the acquisition is the third for the company in the past 12 months.