try: import asyncio except ImportError: print("SKIP") raise SystemExit async def foo(): return 42 try: foo().__await__ except AttributeError: print("SKIP") raise SystemExit try: import time ticks = time.ticks_ms ticks_diff = time.ticks_diff except: import time ticks = lambda: int(time.time() * 1000) ticks_diff = lambda t1, t0: t1 - t0 async def delay_print(t, s): await asyncio.sleep(t) print(s) async def main(): print("start") await asyncio.sleep(0.001) print("after sleep") t0 = ticks() await delay_print(0.2, "short") t1 = ticks() await delay_print(0.4, "long") t2 = ticks() await delay_print(-1, "negative") t3 = ticks() print( "took {} {} {}".format( round(ticks_diff(t1, t0), -2), round(ticks_diff(t2, t1), -2), round(ticks_diff(t3, t2), -2), ) ) asyncio.run(main())