question: public void testCompletedStage ( ) { AtomicInteger x = new AtomicInteger ( 0 ) ; AtomicReference < Throwable > r = new AtomicReference < Throwable > ( ) ; CompletionStage < Integer > f = CompletableFuture . completedStage ( 1 ) ; f . whenComplete ( null ) ; assertEquals ( x . get ( ) , 1 ) ; assertNull ( r . get ( ) ) ; }
target:  completedStage returns a completed CompletionStage