Diplomatic fictions are not to be trifled with, though easy to make fun of.
China's foreign minister, so far, seems to be less aghast than those who prognosticate on China's reaction:
"Chinese Foreign Minister Wang Yi said the call between Taiwan's president and Trump was "just a small trick by Taiwan'' that he believed would not change US policy toward China, according to Hong Kong's Phoenix TV.
"The one-China policy is the cornerstone of the healthy development of China-US relations and we hope this political foundation will not be interfered with or damaged,'' Wang was quoted as saying."
http://timesofindia.indiatimes.com/world/china/China-hopes-Trumps-call-with-Taiwan-leader-wont-damage-ties/articleshow/55766404.cmsTrump noted the shared diplomatic fiction in one his tweets:
"Interesting how the U.S. sells Taiwan billions of dollars of military equipment but I should not accept a congratulatory call."