China is doing what all emerging superpowers have done: tested the limits of other superpowers. The US routinely did this with the Soviet Union, overtly and covertly, on a number of occasions. But the thing is this: China doesn't want war. Sure, it is increasing the size of it's naval forces but they are still a long way away from being a threat to both American interests and assets in the region. Yes, China has an aircraft carrier, but it is their sole aircraft carrier and it was a refurbishment of an old Russian carrier that had been rusting away for close to two decades. And even then, it isn't on par both in size and quite possibly aircraft carried, as it's basically the same size as the sorts of carriers that are currently in service with countries like Italy, Thailand and Spain.
China's navy is still years away from becoming close enough to match that of even the US carrier force in Japan, but neither of the two countries will actually want to go to war with one another. Remember, China is still dependent on American debt. If that debt gets cut off, it could mean a whole world of trouble for the Chinese economy (and pretty much those of US allies like Australia and somewhat NZ who depend on Chinese exports).