public void WithEventEmitter_WhenExceptionRaised_ExceptionIsCaughtAndLogged()
{
const string exceptionMessage = "Listener1 exception";
bool handled1 = false;
bool handled2 = false;
// test logger, logs to memory and set the MessageSeen property if
// the message passed to the constructor is logged;
var logger = new TestLogger(messageToTest: exceptionMessage);
var em = new TestEventEmitter(logger);
List <int> callOrder = new List <int>();
void Listener1(TestEventEmitterArgs args)
{
handled1 = true;
callOrder.Add(1);
throw new Exception(exceptionMessage);
}
void Listener2(TestEventEmitterArgs args)
{
handled2 = true;
callOrder.Add(2);
}
em.On(1, Listener1);
em.On(1, Listener2);
em.DoDummyEmit(1, string.Empty);
handled1.Should().BeTrue();
handled2.Should().BeTrue();
logger.MessageSeen.Should().BeTrue();
callOrder.Count.Should().Be(2);
callOrder[0].Should().Be(1);
callOrder[1].Should().Be(2);
handled1 = handled2 = false;
logger.Reset();
callOrder = new List <int>();
em.Once(1, Listener1);
em.Once(1, Listener2);
em.DoDummyEmit(1, string.Empty);
handled1.Should().BeTrue();
handled2.Should().BeTrue();
callOrder.Count.Should().Be(4);
// On is handled
callOrder[0].Should().Be(1);
callOrder[1].Should().Be(2);
// then Once
callOrder[2].Should().Be(1);
callOrder[3].Should().Be(2);
logger.MessageSeen.Should().BeTrue();
}
public void WithEventEmitter_WhenEmitsEvent_CallsListenersWithEventNameAndArguments()
{
var callList = new List <int>();
var em = new TestEventEmitter(DefaultLogger.LoggerInstance);
TestEventEmitterArgs listener1Args = null;
void Listener1(TestEventEmitterArgs args)
{
callList.Add(1);
em.Off(1, Listener2);
em.On(1, Listener4);
listener1Args = args;
}
void Listener2(TestEventEmitterArgs args)
{
callList.Add(2);
em.Off(1, Listener3);
throw new Exception("should not be hit");
}
void Listener3(TestEventEmitterArgs args)
{
callList.Add(3);
}
void Listener4(TestEventEmitterArgs args)
{
callList.Add(4);
}
void Listener5(TestEventEmitterArgs args)
{
callList.Add(5);
em.Off(1, Listener5);
}
em.On(1, Listener1);
em.On(1, Listener2);
em.On(1, Listener3);
em.On(1, Listener5);
// Listener1 is called first, it subscribes Listener4
// Listener2 is removed by Listener1, but should still be called
// Listener3 is called
// Listener4 is should not be called as it was added by Listener1
// Listener5 is called
em.DoDummyEmit(1, "emit1");
callList.Count.Should().Be(4);
callList[0].Should().Be(1);
callList[1].Should().Be(2);
callList[2].Should().Be(3);
callList[3].Should().Be(5);
listener1Args.Message.Should().Be("emit1");
callList = new List <int>();
// Listener1 is called first, it subscribes Listener4. Listener4 now has 2 subscriptions, but only 1 should fire here
// Listener2 was already removed by Listener, so it is not called
// Listener3 was removed by Listener2, it should not be called
// Listener4 is called once
// Listener5 is not called as it removed itself previously
em.DoDummyEmit(1, "emit2");
callList.Count.Should().Be(2);
callList[0].Should().Be(1);
callList[1].Should().Be(4);
listener1Args.Message.Should().Be("emit2");
callList = new List <int>();
void Listener6(TestEventEmitterArgs args)
{
callList.Add(6);
em.Off();
}
em.On(1, Listener6);
em.DoDummyEmit(1, "emit3");
callList.Count.Should().Be(4);
callList[0].Should().Be(1);
callList[1].Should().Be(4);
callList[2].Should().Be(4);
callList[3].Should().Be(6);
listener1Args.Message.Should().Be("emit3");
callList = new List <int>();
// Listener6 removed all listeners
em.DoDummyEmit(1, "emit4");
callList.Count.Should().Be(0);
listener1Args.Message.Should().Be("emit3");
}
public void WithEventEmitter_WhenOnce_ListenerRegistersForOneEvent()
{
var em = new TestEventEmitter(DefaultLogger.LoggerInstance);
bool t = false;
bool tt = false;
string message = string.Empty;
int counter = 0;
void Reset()
{
t = false;
tt = false;
}
void Handler1(TestEventEmitterArgs args)
{
counter++;
message = args.Message;
t = true;
}
void Handler2(TestEventEmitterArgs args)
{
counter++;
message = args.Message;
tt = true;
}
// no event/state argument, catch all
em.Once(Handler1);
em.Once(Handler1);
em.DoDummyEmit(1, "once");
t.Should().BeTrue();
message.Should().Be("once");
counter.Should().Be(2);
Reset();
// only catch 1 events
em.Once(1, Handler2);
em.DoDummyEmit(2, "on");
// no events should be handled, t & tt should be false here
t.Should().BeFalse();
tt.Should().BeFalse();
// there are 2 listeners and the first is catch all
// but the first should have already handled an event and de-registered
// so the count remains the same
counter.Should().Be(2);
Reset();
em.DoDummyEmit(1, "on");
// t should not have been set, tt should complete for the first time
t.Should().BeFalse();
tt.Should().BeTrue();
// still 2 listeners and we sent a 1 event which second should handle
counter.Should().Be(3);
Reset();
em.DoDummyEmit(1, "on");
// t & tt should both be false
t.Should().BeFalse();
tt.Should().BeFalse();
// handlers should be de-registered so the count should remain at 2
counter.Should().Be(3);
}
public void WithEventEmitter_WhenOff_DeRegistersForEvents()
{
var em = new TestEventEmitter(DefaultLogger.LoggerInstance);
string message = string.Empty;
int counter = 0;
void Reset()
{
counter = 0;
}
void Listener1(TestEventEmitterArgs args)
{
counter++;
message = args.Message;
}
void Listener2(TestEventEmitterArgs args)
{
counter++;
message = args.Message;
}
// if called with no arguments, it removes all registrations, for all events and listeners
em.On(1, Listener1);
em.On(2, Listener1);
em.On(3, Listener1);
em.DoDummyEmit(1, "off");
message.Should().Be("off");
counter.Should().Be(1);
Reset();
em.Off();
em.DoDummyEmit(1, "off");
em.DoDummyEmit(2, "off");
em.DoDummyEmit(3, "off");
counter.Should().Be(0);
Reset();
em.On(1, Listener1);
em.On(2, Listener2);
em.On(1, Listener2);
em.DoDummyEmit(1, "off");
message.Should().Be("off");
counter.Should().Be(2);
Reset();
em.Off();
em.DoDummyEmit(1, "off");
em.DoDummyEmit(2, "off");
counter.Should().Be(0);
Reset();
// if called only with a listener, it removes all registrations matching the given listener,
// regardless of whether they are associated with an event or not
em.On(1, Listener1);
em.On(1, Listener2);
em.DoDummyEmit(1, "off");
counter.Should().Be(2);
Reset();
em.Off(Listener2);
em.DoDummyEmit(1, "off");
counter.Should().Be(1);
Reset();
em.Off(Listener1);
em.DoDummyEmit(1, "off");
counter.Should().Be(0);
// If called with a specific event and a listener,
// it removes all registrations that match both the given listener and the given event
em.On(1, Listener1);
em.On(1, Listener2);
em.On(2, Listener1);
Reset();
em.DoDummyEmit(1, "off");
counter.Should().Be(2);
Reset();
em.DoDummyEmit(2, "off");
counter.Should().Be(1);
Reset();
// no handler for this event, so this should have no effect
em.Off(3, Listener1);
em.DoDummyEmit(1, "off");
counter.Should().Be(2);
Reset();
// no handler for this listener, so this should have no effect
em.Off(2, Listener2);
em.DoDummyEmit(1, "off");
counter.Should().Be(2);
Reset();
// remove handler 1 of 2 remaining
em.Off(1, Listener1);
em.DoDummyEmit(1, "off");
counter.Should().Be(1);
Reset();
// remove the final handler
em.Off(1, Listener2);
em.DoDummyEmit(1, "off");
counter.Should().Be(0);
}
public void WithEventEmitter_WhenOn_ListenerRegistersForRepeatedEvents()
{
var em = new TestEventEmitter(DefaultLogger.LoggerInstance);
string message = string.Empty;
int counter = 0;
int handledCounter1 = 0;
int handledCounter2 = 0;
bool handled1 = false;
bool handled2 = false;
// no event/state argument, catch all
void Handler1(TestEventEmitterArgs args)
{
counter++;
handledCounter1++;
message = args.Message;
handled1 = true;
}
void Handler2(TestEventEmitterArgs args)
{
counter++;
handledCounter2++;
message = args.Message;
handled2 = true;
}
void Reset()
{
handled1 = false;
handled2 = false;
}
// add Handler1 as a catch all
em.On(Handler1);
em.DoDummyEmit(1, "on");
handled1.Should().BeTrue();
message.Should().Be("on");
// currently one listener
counter.Should().Be(1);
handledCounter1.Should().Be(1);
handledCounter2.Should().Be(0);
Reset();
// add another Handler1 as a catch all
em.On(Handler1);
em.DoDummyEmit(1, "on");
handled1.Should().BeTrue();
counter.Should().Be(3);
handledCounter1.Should().Be(3);
// only catch 1 events
em.On(1, Handler2);
em.DoDummyEmit(2, "on");
// handled2 should be false here
handled1.Should().BeTrue();
handled2.Should().BeFalse();
// now there should be 3 listeners, the first is 2 are catch all
handledCounter1.Should().Be(5);
handledCounter2.Should().Be(0);
counter.Should().Be(5);
Reset();
em.DoDummyEmit(1, "on");
handled1.Should().BeTrue();
handled2.Should().BeTrue();
handledCounter1.Should().Be(7);
handledCounter2.Should().Be(1);
// still 2 listeners and we sent a 1 event which both should handle
counter.Should().Be(8);
Reset();
}