Apple is about to face a big test of its ability to manufacture its devices outside China—by making a brand-new product in Vietnam.  

Apple has tapped factories in Vietnam to make its own forthcoming over-ear headphones, a new phase in its effort to diversify manufacturing away from China amid political and trade tensions between Washington and Beijing, The Information has learned. The move would be the first time Apple has used factories in Vietnam to produce an entirely new product, instead of relying on them to supplement manufacturing of an older model already produced in China. The company is working with contract manufacturers, who will also build some of the headphones in factories in China, said a person briefed on Apple’s plans.