Add test

trans/stdlib/typon/__init__.py

@@ -20,6 +20,7 @@ def fork(f: Callable[[], T]) -> Task[Forked[T]]:
         get = f
     return Res
 
+assert fork(lambda: 1).get
 
 def future(f: Callable[[], T]) -> Task[Future[T]]:
     # stub