Fixed ServerLowLevel tests not running

[hylkevds]

JUnit only runs tests in classes that have a name that ends in Test,
the class in question had a name that ended in Tests, with an added s.
As a result, the tests in this class were never executed. This renames
the class to not have the added s.

[hylkevds]

The first commit fixes the tests not running, the second commit adds a test for #573.
So the builds should all fail after the second commit, and be fixed again by PR #576.

[andsel]

Hi @hylkevds the test is usefull, I would suggest some changes to be more explicit why some magic numbers are the values they are.

[andsel]

12 seconds is more then 2 times of resend interval (

moquette/broker/src/main/java/io/moquette/broker/Session.java

Line 37 in f6f3f6e

private static final int FLIGHT_BEFORE_RESEND_MS = 5_000;

) this direct linkage with this interval should be more explicit, so:

• move from private to package private or even public that constant and reuse here as FLIGHT_BEFORE_RESEND_MS * 2

[hylkevds]

I agree using the constant is much nicer, but Session would also have to be made public for that to work...
Another option is to make a separate class for constants.
What would you prefer?

[andsel]

The countdown latch initialized to 2 is redundant. It should be initialized to 1 and countDown() only when it reaches the second publish.

It could be done even more straightforward with Awaitility, for example:

AtomicBoolean isFirst = new AtomicBoolean(true);
AtomicBoolean receivedPublish = new AtomicBoolean(false);
subscriber.subscribe(topic, 1, (String topic1, org.eclipse.paho.client.mqttv3.MqttMessage message) -> {
  if (isFirst.getAndSet(false)) {
    TimeUnit.MILLISECONDS.sleep(FLIGHT_BEFORE_RESEND_MS * 2);
  } else {
    receivedPublish.set(true); 
  }
});
publisher.publish(topic, "hello".getBytes(), 1, false);

Awaitility.await()
    .atMost(FLIGHT_BEFORE_RESEND_MS * 4, TimeUnit.MILLISECONDS)
    .pollInterval(FLIGHT_BEFORE_RESEND_MS, TimeUnit.MILLISECONDS)
    .untill(receivedPublish::get, equalTo(true));
   

[andsel]

Is better is we move those two constants into broker/src/main/java/io/moquette/BrokerConstants.java wihtou changing visibility of Session class

[hylkevds]

Ok, I'll do that, and clean up the test.

[andsel]

LGTM