Wait for unit tests to consume events

On #27053 Dave's reported that even with a bumped sleep these new tests occasionally fail for him. Sleeps within tests are a code stink so I really should do something smarter anyway. Waiting up to five seconds for unit tests to consume the events they emit. When we run both our unit and integ tests the later performs heavy tests asychrously. This tends to peg the CPU while running our unit tests, probably slowing things down enough for them to fail occasionly for Dave.

Wait for unit tests to consume events
c9cc0f55 · Damian Johnson · bc06836e · c9cc0f55
Commit c9cc0f55 authored Aug 12, 2018 by Damian Johnson
--- a/test/unit/control/controller.py
+++ b/test/unit/control/controller.py
@@ -826,7 +826,14 @@ class TestControl(unittest.TestCase):
    self.controller._event_queue.put(uncast_event)
    self.controller._event_notice.set()

-    # doesn't seem necessary in practice, but since event processing is
-    # asynchronous giving it a tiny bit of time to get handled
+    # Wait for the event to get asynchronously consumed. This should happen
+    # right away, but if the system is bogged down it may take quite a few
+    # milliseconds.

-    time.sleep(0.03)
+    event_sent_at = time.time()
+
+    while not self.controller._event_queue.empty():
+      time.sleep(0.01)
+
+      if time.time() - event_sent_at > 5:
+        self.fail('Event did not get processed after five seconds')