For over twenty years China has imported two Russian engines similar to the WS10A. The two main ones are the $3.5 million AL31 for the Su-27/30 aircraft and the $2.5 million RD93 (a version of the MiG-29's RD33) for the JF-17 (an F-16 type aircraft developed in cooperation with Pakistan). During all this, Chinese engineers worked to master the manufacturing techniques needed to make a Chinese copy of the Russian AL31F engine. That was part of a program that has also developed the WS-13, to replace the RD93 as well. While the Chinese have been able to build engines that are competitive on paper, and during ground tests, they are still having problems with reliability and durability when they install the WS10A in aircraft.
China has long copied foreign technology, not always successfully. But in the last decade, China has poured a lot of money into developing a jet engine manufacturing capability. The Chinese encountered many of the same problems the Russians did when developing their own engine design and construction skills. But China has several advantages. First, they knew of the mistakes the Russians had made, and so were able to avoid many of them. Then there was the fact that China had better access to Western manufacturing technology (both legally and illegally). Finally, China was, unlike the Soviets, able to develop their engine manufacturing capabilities in a market economy. This was much more efficient than the command economy that the Soviets were saddled with for seven decades. Despite all this, China continued to encounter problems with consistent quality in manufacturing key components. China is determined to master Russian engine building techniques, and then move on to beating the Western firms who have long been the masters of this technology.