def test_subscriber_wait_for_message(self):
"""Checks how `WaitForMessage` works without Python threads."""
lcm = DrakeLcm()
sub = mut.LcmSubscriberSystem.Make("TEST_LOOP", lcmt_header, lcm)
value = AbstractValue.Make(lcmt_header())
for old_message_count in range(3):
message = lcmt_header()
message.utime = old_message_count + 1
lcm.Publish("TEST_LOOP", message.encode())
for attempt in range(10):
new_count = sub.WaitForMessage(old_message_count,
value,
timeout=0.02)
if new_count > old_message_count:
break
lcm.HandleSubscriptions(0)
self.assertEqual(value.get_value().utime, old_message_count + 1)
def AllocateOutput(self):
return AbstractValue.Make(lcmt_header())