It is NOT in China's interest to formally with Iran.
It forces many more countries to choose the USA, when they would prefer to remain neutral in any USA-China contest.
That is the bottom line
China cannot afford to ruin its relationship with Saudi Arabia and Isreal.why would china ally with Iran and then ruins its relationship with Saudi , Quatar, UAE , Israel ,USA ? Basically IRAN is a no no for china.
China Restarts Purchases of Iranian Oil, Bucking Trump’s Sanctions
biggest issue is Trump could go after company like Sinopec in term of financial transaction and other area. world financial service still dominated by US, new york etc. EU/China try to find alternative with limited success.I do not know how reliable the news site is. If it's UN sanction, then China should respect it. But I do not see any compelling reason why China should obey America's unilateral sanction against Iran, which is America's domestic law.
I think it is quite simple. China should just make a separate company which handles Iranian and Venezuelan oil.
Then sell it in the internal Chinese market. Good luck to the US stopping it.