与Nunit的测试活动

可以通过订阅该事件并设置布尔值来检查是否触发了事件:

var wasCalled = false;
foo.NyEvent += (o,e) => wasCalled = true;

...

Assert.IsTrue(wasCalled);

根据要求-不含羔羊:

var wasCalled = false;
foo.NyEvent += delegate(o,e){ wasCalled = true;}

...

Assert.IsTrue(wasCalled);

我喜欢这样做:

var wait = new AutoResetEvent(false);
foo.MeEvent += (sender, eventArgs) => { wait.Set(); };
Assert.IsTrue(wait.WaitOne(TimeSpan.FromSeconds(5)));

优点:支持多线程场景(如果在不同线程中调用了处理程序)

如果您知道事件将同步激发:

bool eventRaised = false;
Customer customer = new Customer() { Name = "Carl" };
customer.NameChanged += (sender, e) => { eventRaised = true; };

customer.Name = "Sam";

Assert.IsTrue(eventRaised);

如果可以异步触发事件:

ManualResetEvent eventRaised = new ManualResetEvent(false);
Customer customer = new Customer() { Name = "Carl" };
customer.NameChanged += (sender, e) => { eventRaised.Set(); };

customer.Name = "Sam";

Assert.IsTrue(eventRaised.WaitOne(TIMEOUT));

然而,一些人认为应该避免测试异步行为。

我最近不得不这么做,下面是我的想法。我没有像其他帖子所说的那样做,原因是我不喜欢变量保持状态的想法,并且必须在多个事件之间“手动”重置它。

下面是 ClassUnderTest 具有 NameChanged 测试的事件 MyTests 测验:

public class ClassUnderTest {
    private string name;
    public string Name {
        get { return this.name; }
        set {
            if (value != this.name) {
                this.name = value;
                NameChanged(this, new PropertyChangedEventArgs("Name"));
            }
        }
    }

    public event EventHandler<PropertyChangedEventArgs> NameChanged = delegate { };
}

[TestFixture]
public class MyTests {
    [Test]
    public void Test_SameValue() {
        var t = new ClassUnderTest();
        var e = new EventHandlerCapture<PropertyChangedEventArgs>();
        t.NameChanged += e.Handler;

        Event.Assert(e, Event.IsNotRaised<PropertyChangedEventArgs>(), () => t.Name = null);
        t.Name = "test";
        Event.Assert(e, Event.IsNotRaised<PropertyChangedEventArgs>(), () => t.Name = "test");
    }
    [Test]
    public void Test_DifferentValue() {
        var t = new ClassUnderTest();
        var e = new EventHandlerCapture<PropertyChangedEventArgs>();
        t.NameChanged += e.Handler;

        Event.Assert(e, Event.IsPropertyChanged(t, "Name"), () => t.Name = "test");
        Event.Assert(e, Event.IsPropertyChanged(t, "Name"), () => t.Name = null);
    }
}

支持类如下。这些类可以与任何 EventHandler<TEventArgs> 或者扩大到其他代表。事件测试可以嵌套。

/// <summary>Class to capture events</summary>
public class EventHandlerCapture<TEventArgs> where TEventArgs : EventArgs {
    public EventHandlerCapture() {
        this.Reset();
    }

    public object Sender { get; private set; }
    public TEventArgs EventArgs { get; private set; }
    public bool WasRaised { get; private set; }

    public void Reset() {
        this.Sender = null;
        this.EventArgs = null;
        this.WasRaised = false;
    }

    public void Handler(object sender, TEventArgs e) {
        this.WasRaised = true;
        this.Sender = sender;
        this.EventArgs = e;
    }
}

/// <summary>Contains things that make tests simple</summary>
public static class Event {
    public static void Assert<TEventArgs>(EventHandlerCapture<TEventArgs> capture, Action<EventHandlerCapture<TEventArgs>> test, Action code) where TEventArgs : EventArgs {
        capture.Reset();
        code();
        test(capture);
    }
    public static Action<EventHandlerCapture<TEventArgs>> IsNotRaised<TEventArgs>() where TEventArgs : EventArgs {
        return (EventHandlerCapture<TEventArgs> test) => {
            NUnit.Framework.Assert.That(test.WasRaised, Is.False);
        };
    }
    public static Action<EventHandlerCapture<PropertyChangedEventArgs>> IsPropertyChanged(object sender, string name) {
        return (EventHandlerCapture<PropertyChangedEventArgs> test) => {
            NUnit.Framework.Assert.That(test.WasRaised, Is.True);
            NUnit.Framework.Assert.That(test.Sender, Is.SameAs(sender));
            NUnit.Framework.Assert.That(test.EventArgs.PropertyName, Is.EqualTo(name));
        };
    }
}

我自己并没有这样做,但也许你可以向你想要订阅的事件添加一个虚拟的事件处理程序,并让它更新一个本地布尔变量,这样在方法被激发之后,你可以检查该布尔变量的状态,看是否触发了该事件?

类似:

bool eventFired = false;
foo.MyEvent += (s, e) => { eventFired = true };

Assert.IsTrue(eventFired);

@烧僧:一个“;”不见了。修正版本为:

bool eventFired = false;
foo.MyEvent += (s, e) => { eventFired = true; };
Assert.IsTrue(eventFired);

干杯!;-)

使用nunit和moq,您可以进行更健壮的事件测试。

用于监视事件触发器的模拟类:

public class AssertEvent { public virtual void Call(string obj) { } }
Mock<AssertEvent> EventMock;
AssertEvent Evt;

事件触发器的设置:

[SetUp]
public void TestInit() {
    EventMock = new Mock<AssertEvent>();
    Evt= EventMock.Object;
}

在测试中使用模拟对象:

[Test]
public void TestMethod() {
    myObject.Event1 += (sender, args) => Evt.Call("Event1Label");
    myObject.Event2 += (sender, args) => Evt.Call("Event2Label");
    myObject.Event3 += (sender, args) => Evt.Call("Event3Label");        

    myObject.SomeEventTrigger();

    EventMock.Verify(m => m.Call("Event1Label"), Times.Exactly(1));
    EventMock.Verify(m => m.Call("Event2Label"), Times.Never());
    EventMock.Verify(m => m.Call("Event3Label"), Times.Between(1,3);

}

您可以添加您的自定义事件处理程序,例如,它会在测试用例类中增加一些整数字段。然后检查字段是否递增。