Test cl-gserver/tests/actor-test.lisp not actually good

[Yehouda]

cl-gserver/tests/actor-test.lisp

Line 525 in fbc471b

(test actor-of--limit-queue-size

The test assumes that tell will succed only once, but if the actor starts up it may take one of the events before the loop calling tell ends, in which case two calls will succeed.
In our version I changed it to:

1. sleep before starting the loop, so always two calls are succeessful.
2. check for 2 successes and 8 failures, rather than 1 and 9.
3. also sleep before the shutdown.

BTW: the fact that shutdown error if any of the actors has a full queue looks to me like a bug, or at least a mis-feature. There should be a way to shutdown the system independently of what the actors do.

(test actor-of--limit-queue-size
         "Tests that actor's queue size can be limited."
         (let ((sys (asys:make-actor-system)))
           (unwind-protect
               (let* ((actor (actor-of sys
                                       :receive (lambda (msg)
                                                  (declare (ignore msg))
                                                  (sleep 0.05))
                                       :queue-size 1))
                      (tells
                       (progn (sleep 0.01) ; make sure the actor started
                         (loop :repeat 10

                               :collect (ignore-errors
                                          (tell actor "run"))))))
                 (format t "tells: ~a~%" tells)
                 (is (= 2 (length (filter (lambda (x) (if x x)) tells))))
                 (is (= 8 (length (filter #'null tells)))))
             (sleep 0.1)
             (ac:shutdown sys))))

[mdbergmann]

Yeah, you are right. This test is a bit flaky.
Dealing with timings is always problematic.
actor-of returns a fully initialized actor ready to process messages, so I'm not sure the initial sleep is necessary.
The 2/8 partitioning is a good idea. Could be a bit more reliable.

The problem with shutdown are the threads that are trying to pop the mailbox queue. If there is no message in the queue the pop operation the thread executes will block. So in order to leave a clean system after ac:shutdown one has to make sure the threads are properly stopped/cancelled.