Get rid of unreliable TimerTest

[chrjohn]

Follow-up to #345

IIRC only on the MacOS Java CI jobs we could observe that the next() method was triggered unreliably (usually this should be called every second). As a result the check whether a Heartbeat should be sent was sometimes called too late. This lead to failures in the TimerTest.

2020-12-31T22:09:00.0063950Z <20201231-22:09:00, FIX.4.4:TW->ISLD, incoming> (8=FIX.4.4�9=60�35=A�34=1�49=ISLD�52=20201231-22:09:00.005�56=TW�98=0�108=2�10=143�)
2020-12-31T22:09:00.0065060Z <20201231-22:09:00, FIX.4.4:TW->ISLD, event> (Received logon)
2020-12-31T22:09:00.0066220Z XXX FIX.4.4:TW->ISLD isHeartBeatNeeded() = false
# more than one second pause
2020-12-31T22:09:01.0259920Z XXX FIX.4.4:ISLD->TW isHeartBeatNeeded() = false
2020-12-31T22:09:01.0261070Z XXX FIX.4.4:TW->ISLD isHeartBeatNeeded() = false
# less than one second pause
2020-12-31T22:09:01.9287190Z XXX FIX.4.4:ISLD->TW isHeartBeatNeeded() = false
2020-12-31T22:09:01.9288290Z XXX FIX.4.4:TW->ISLD isHeartBeatNeeded() = false
# more than one second pause
2020-12-31T22:09:03.0341840Z <20201231-22:09:03, FIX.4.4:ISLD->TW, outgoing> (8=FIX.4.4�9=58�35=1�34=2�49=ISLD�52=20201231-22:09:03.029�56=TW�112=TEST�10=186�)
2020-12-31T22:09:03.0343040Z <20201231-22:09:03, FIX.4.4:ISLD->TW, event> (Sent test request TEST)

I decided to get rid of the TimerTest since in the wild this unreliable triggering of heartbeats would be not a big problem and especially the heartbeat interval of 2 seconds that the test used was ridiculously low. So for a normal heartbeat interval of 30 seconds there is no problem when the heartbeat is generated say 100ms too late.

TimerTest was replaced by a simple unit test with a few lines:

quickfixj/quickfixj-core/src/test/java/quickfix/SessionStateTest.java

Lines 73 to 88 in 19fd341

	@Test
	public void testHeartbeatTiming() {
	// we set a HB interval of 2 seconds = 2000ms
	SessionState state = new SessionState(new Object(), null, 2 /* HB interval */, false, null,
	Session.DEFAULT_TEST_REQUEST_DELAY_MULTIPLIER, Session.DEFAULT_HEARTBEAT_TIMEOUT_MULTIPLIER);
	long now = System.currentTimeMillis();
	timeSource.setSystemTimes(now);
	state.setLastSentTime(now);
	assertFalse("heartbeat shouldn't be needed yet", state.isHeartBeatNeeded());
	timeSource.increment(1000);
	assertFalse("heartbeat shouldn't be needed yet", state.isHeartBeatNeeded());
	timeSource.increment(1000);
	// current time is now 2000ms further since the start, i.e. the HB interval has elapsed
	assertTrue("heartbeat should be needed", state.isHeartBeatNeeded());
	}