Testing things with Rhino mocks and the AAA syntax is simple. But sometimes I need a reminder of the correct syntax. And sometimes the result is not what I would expect. But then that’s what my users say about my programs too ;-).
I wrote a little testcase to see if I could reproduce the same result. And like I said before Rhino moccks’ AAA syntax is much easier to use in C# but I will make a VB.Net version for this too. So don’t worry.
The problem is understanding the difference between raising an event that has a delegate without parameters and raising an event that has parameters. Let me show you the code first.
```csharp using System; using Rhino.Mocks; using NUnit.Framework;
namespace TestingRhinoMocks { public delegate void MyDelegate1(); public delegate void MyDelegate2(string test); public delegate void MyDelegate3(string test1, int test2); public delegate void MyDelegate4(object test); public delegate void MyDelegate5(object test1, object test2); public delegate void MyDelegate6(object test1, object test2, Object test3);
public interface IEventsRaiser
{
event MyDelegate1 event1;
event MyDelegate2 event2;
event MyDelegate3 event3;
event MyDelegate4 event4;
event MyDelegate5 event5;
event MyDelegate6 event6;
}
public class EventRaiser : IEventsRaiser
{
public event MyDelegate1 event1;
public event MyDelegate2 event2;
public event MyDelegate3 event3;
public event MyDelegate4 event4;
public event MyDelegate5 event5;
public event MyDelegate6 event6;
}
public class EventConsumer
{
private IEventsRaiser eventraiser;
public EventConsumer(IEventsRaiser eventraiser)
{
this.eventraiser = eventraiser;
eventraiser.event1 += Eventhandler1;
eventraiser.event2 += Eventhandler2;
eventraiser.event3 += Eventhandler3;
eventraiser.event4 += Eventhandler4;
eventraiser.event5 += Eventhandler5;
eventraiser.event6 += Eventhandler6;
}
public string Message { get; set; }
public void Eventhandler1()
{
Message = "Eventhandler1";
}
public void Eventhandler2(string test)
{
Message = "Eventhandler2";
}
public void Eventhandler3(string test1, int test2)
{
Message = "Eventhandler3";
}
public void Eventhandler4(object test)
{
Message = "Eventhandler4";
}
public void Eventhandler5(object test1, object test2)
{
Message = "Eventhandler5";
}
public void Eventhandler6(object test1, object test2, Object test3)
{
Message = "Eventhandler6";
}
}
[TestFixture]
public class TestRaiseEvents
{
private IEventsRaiser eventraiser;
private EventConsumer eventsConsumer;
[SetUp]
public void SetUp()
{
eventraiser = MockRepository.GenerateMock<IEventsRaiser>();
eventsConsumer = new EventConsumer(eventraiser);
}
[Test]
public void Test_raising_event1_without_parameters_using_raise()
{
Assert.IsNull(eventsConsumer.Message);
eventraiser.Raise(e => e.event1 += null);
Assert.AreEqual("Eventhandler1", eventsConsumer.Message);
}
[Test]
[ExpectedException(ExceptionName = "System.InvalidOperationException", ExpectedMessage = "You have called the event raiser with the wrong number of parameters. Expected 0 but was 0")]
public void Test_raising_event1_without_parameters_using_geteventraiser_and_raise()
{
Assert.IsNull(eventsConsumer.Message);
eventraiser.GetEventRaiser(e => e.event1 += null).Raise(null);
Assert.AreEqual("Eventhandler1", eventsConsumer.Message);
}
[Test]
[ExpectedException(ExceptionName = "System.InvalidOperationException", ExpectedMessage = "You have called the event raiser with the wrong number of parameters. Expected 1 but was 0")]
public void Test_raising_event2_with_parameters_wrongly_called()
{
Assert.IsNull(eventsConsumer.Message);
eventraiser.Raise(e => e.event2 += null);
Assert.AreEqual("Eventhandler2", eventsConsumer.Message);
}
[Test]
public void Test_raising_event2_with_parameters()
{
Assert.IsNull(eventsConsumer.Message);
eventraiser.GetEventRaiser(e => e.event2 += null).Raise("test");
Assert.AreEqual("Eventhandler2", eventsConsumer.Message);
}
[Test]
public void Test_raising_event3_with_parameters()
{
Assert.IsNull(eventsConsumer.Message);
eventraiser.GetEventRaiser(e => e.event3 += null).Raise("test", 0);
Assert.AreEqual("Eventhandler3", eventsConsumer.Message);
}
[Test]
public void Test_raising_event4_with_parameters()
{
Assert.IsNull(eventsConsumer.Message);
eventraiser.GetEventRaiser(e => e.event4 += null).Raise(new Object());
Assert.AreEqual("Eventhandler4", eventsConsumer.Message);
}
[Test]
public void Test_raising_event5_with_parameters()
{
Assert.IsNull(eventsConsumer.Message);
eventraiser.GetEventRaiser(e => e.event5 += null).Raise(new Object(), new Object());
Assert.AreEqual("Eventhandler5", eventsConsumer.Message);
}
[Test]
public void Test_raising_event6_with_parameters()
{
Assert.IsNull(eventsConsumer.Message);
eventraiser.GetEventRaiser(e => e.event6 += null).Raise(new Object(), new Object(), new Object());
Assert.AreEqual("Eventhandler6", eventsConsumer.Message);
}
}
}``` As always the code speaks for itself ;-). But I’ll try to explain it anyway. I have a class that raisesevents and an interface for that class so I can mock it easily. Then I have a class that consumes the events. I used 6 different events with different signatures just to prove that it works like I think it should.
So Test number 1 has the correct syntax to raise an event that takes no parameters. Namely eventraiser.Raise(e => e.event1 += null); We use the extension method Raise to raise the event on our mock. Now this is different from raising an event that has parameters in the way that eventraiser.GetEventRaiser(e => e.event2 += null).Raise(“test”); uses GetEventRaiser and then the method Raise to add the parameter. If we try to use the same syntax on the parameterless event like so eventraiser.GetEventRaiser(e => e.event1 += null).Raise(null); we get an InvalidOperationException (You have called the event raiser with the wrong number of parameters. Expected 0 but was 0). Expected 0 but was 0 doesn’t sound completely right but I get the picture. If you try to raise an event on a parameterd event like you would on a parameterless event, like so eventraiser.Raise(e => e.event2 += null); then you get this InvalidOperationException (You have called the event raiser with the wrong number of parameters. Expected 1 but was 0) where the 1 is the number of parameters you should have.
I hope everything is clear now on how to raise an event on a mock object.
I used Rhino mocks 3.5.0.1337 for this.
Comments welcome.
Chris is awesome.
