Add test for issue #25 - periodic timers overlapping single-shot timers.

tests/issue-25-periodic-timers.d

@@ -0,0 +1,68 @@
+/++ dub.sdl:
+	name "test"
+	dependency "eventcore" path=".."
++/
+module test;
+
+import eventcore.core;
+import std.datetime : Clock, SysTime, UTC;
+import std.stdio : writefln;
+import core.time : Duration, msecs;
+
+SysTime s_startTime;
+int s_cnt = 0;
+bool s_done;
+
+void main()
+{
+	s_startTime = Clock.currTime(UTC());
+
+	bool timer1fired = false;
+
+	// first timer: one-shot 200ms
+	auto tm = eventDriver.timers.create();
+	eventDriver.timers.wait(tm, (tm) nothrow @safe {
+		scope (failure) assert(false);
+		writefln("First timer");
+
+		auto dur = Clock.currTime(UTC()) - s_startTime;
+		assert(dur > 200.msecs);
+		assert(dur < 220.msecs);
+
+		timer1fired = true;
+	});
+	eventDriver.timers.set(tm, 200.msecs, 0.msecs);
+
+	// second timer repeating 100ms, 3 times
+	auto tm2 = eventDriver.timers.create();
+	eventDriver.timers.set(tm2, 100.msecs, 100.msecs);
+	void periodicCallback(TimerID timer) nothrow @safe {
+		try {
+			writefln("Second timer");
+
+			auto dur = Clock.currTime(UTC()) - s_startTime;
+			s_cnt++;
+			assert(dur > 100.msecs * s_cnt);
+			assert(dur < 100.msecs * s_cnt + 20.msecs);
+			assert(s_cnt <= 3);
+
+			if (s_cnt == 3) {
+				s_done = true;
+				eventDriver.timers.stop(timer);
+				assert(timer1fired, "Timer 1 didn't fire within 300ms");
+			} else eventDriver.timers.wait(tm2, &periodicCallback);
+		} catch (Exception e) {
+			assert(false, e.msg);
+		}
+	}
+
+	eventDriver.timers.wait(tm2, &periodicCallback);
+
+
+	ExitReason er;
+	do er = eventDriver.core.processEvents(Duration.max);
+	while (er == ExitReason.idle);
+	assert(er == ExitReason.outOfWaiters);
+	assert(s_done);
+	s_done = false;
+}