Of course, it's a test of the Chinese aerospace industry if they are able to develope, produce and maintain a state-of-the-art engine for the own next-gen fighter.
There is no excuse if the first batch of J-20s fighters flying with Russian engines.
People are saying WS15 is in development. Well who knows what that mean. And who know how long it takes. It doesn't mean much at this point
If the first batch of J20 still using Russian Engine is "major disappointment" to say the least and there's no other ways to sweeten it. And Supercruise is not even a requirement at initial stage and if China still can't pull it off then there's no excuse to it.
Even the Hongkong and Taiwan media commented the J20 project is fake (face project) due to its inability to get its own engine.