Well, China once chose to arm Iran like it is doing right now to Pakistan.
But obviously Iran rejected China's offer, and prefer the western/Russia weapons over China's.
Even Israel's reputation as nation isn't so great, but what's China's pretext to strike them?
Before the 5.7 air battle, India wanted to use the terrorist attack as a pretext to annex Pakistan, then aimed at China.
Even with a such malicious intention, China chose to not participate the war directly, but fully armed Pakistan to the teeth.
The problem is that China's leadership right now totally distrusts Iran, and not sure if they are willing to cooperate with Iran again.