如何对RuntimeType进行单元测试

Question

[Test]
// arrange 
// ...
// act
var result = (Car) service.GetCar(req);

// assert
Assert.AreEqual(result, typeof(Car));  

But I'm getting following error

Expected: <Models.Car> (Car)    
But was:  <Models.Car> (RuntimeType)

I tried to change assert to use Is.InstanceOf :

Assert.AreEqual(result, Is.InstanceOf<Car>());

But I'm still getting error, this time

Expected: <Models.Car>
But was:  <<instanceof Models.Car>>

Answer 1

You don't need to cast the result of service.GetCar(req) . This would work:

var result = service.GetCar(req);

Assert.IsInstanceOf<Car>(result);

Or, as an alternative, use:

var result = service.GetCar(req);

Assert.That(result, Is.TypeOf<Car>());

Answer 2

Following means that you want to compare object and type, while you want to compare type of the object: Assert.AreEqual(result, typeof(Car));

You could use: Assert.AreEqual(result.GetType(), typeof(Car)); , but I'm not sure if this will work.

But the best option is to try casting and failing if cast is not successfull:

try
{
    var result = (Car) service.GetCar(req);
}
catch (Exception ex)
{
    Assert.Fail();
}

or you could use Assert.ThrowsException() method to check if exception been thrown, but it's not straightforwards, as previous method.

Action action = () => { var result = (Car) service.GetCar(req); };
Assert.ThrowsException<Exception>(action);