public void When_multiple_consequenter_handlers_are_chained_then_the_last_added_is_called_first()
{
// arrange
var bus = new InProcessEventBus();
var handlerCalls = new List <string>();
// act
var handler = new TestConsequenter()
.WrapAll((e, next) =>
{
handlerCalls.Add("c");
next(e);
})
.WrapAll((e, next) =>
{
handlerCalls.Add("b");
next(e);
})
.WrapAll((e, next) =>
{
handlerCalls.Add("a");
next(e);
});
bus.Subscribe(handler);
bus.PublishAsync(new Order.Created()).Wait();
// assert
handlerCalls.Should().BeInAscendingOrder();
}
public async Task When_a_handler_chain_throws_then_subsequent_events_are_still_published()
{
// arrange
var bus = new InProcessEventBus();
var errors = new List <EventHandlingError>();
bus.Errors.Subscribe(errors.Add);
var callCount = 0;
// act
var handler = new TestConsequenter()
.WrapAll((e, next) =>
{
callCount++;
if (callCount == 1)
{
throw new Exception("oops!");
}
});
bus.Subscribe(handler);
await bus.PublishAsync(new Order.Created());
await bus.PublishAsync(new Order.Created());
// assert
callCount.Should().Be(2);
}
public void When_a_consequenter_that_has_been_chained_throws_then_the_EventHandlingError_Handler_references_the_inner_handler()
{
// arrange
var bus = new InProcessEventBus();
var errors = new List <EventHandlingError>();
bus.Errors.Subscribe(errors.Add);
// act
var handler = new TestConsequenter(onCreated: e => { throw new Exception("oops!"); });
bus.Subscribe(handler);
bus.PublishAsync(new Order.Created()).Wait();
// assert
errors.Should().ContainSingle(e => e.Handler is TestConsequenter);
}
public void When_a_handler_chain_throws_then_an_EventHandlingError_is_published()
{
// arrange
var bus = new InProcessEventBus();
var errors = new List <EventHandlingError>();
bus.Errors.Subscribe(errors.Add);
// act
var handler = new TestConsequenter()
.WrapAll((e, next) => { throw new Exception("oops!"); });
bus.Subscribe(handler);
bus.PublishAsync(new Order.Created()).Wait();
// assert
errors.Should().ContainSingle(e => e.StreamName == "Order" &&
e.Event.EventName() == "Created" &&
e.Exception.Message.Contains("oops!"));
}
public void Consequenter_can_be_short_circuited_using_handler_chains()
{
// arrange
var bus = new InProcessEventBus();
var consequenterWasCalled = false;
var handlerCalls = 0;
// act
var handler = new TestConsequenter(onCreated: e => consequenterWasCalled = true)
.WrapAll((e, next) =>
{
handlerCalls++;
// by not calling next, we short circuit the call to the remaining handler chain
});
bus.Subscribe(handler);
bus.PublishAsync(new Order.Created()).Wait();
// assert
handlerCalls.Should().Be(1);
consequenterWasCalled.Should().BeFalse();
}