How the statement return new Enumeration() is possible, since Enumeration is an Interface. Plz explain. Thanks.
public Enumeration<E> elements() {
return new Enumeration<E>() {
int count = 0;
public boolean hasMoreElements() {
return count < elementCount;
}
public E nextElement() {
synchronized (Vector.this) {
if (count < elementCount) {
return elementData(count++);
}
}
throw new NoSuchElementException("Vector Enumeration");
}
};
}
It is possible because it implements the Enumeration interface through an anonymous inner class.
Interfaces are defined to be implemented, and the use of an anonymous inner class is simply a shortcut, that works the same way as when you instantiate an abstract class (you must implement the abstract methods). In this case, you must implement ALL of the interface methods.
Related
I have a following problem. I register my components and initialize them in Unity like this (example is for a Console application):
public class SharePointBootstrapper : UnityBootstrapper
{
...
public object Initialize(Type type, object parameter) =>
Container.Resolve(type,
new DependencyOverride<IClientContext>(Container.Resolve<IClientContext>(parameter.ToString())),
new DependencyOverride<ITenantRepository>(Container.Resolve<ITenantRepository>(parameter.ToString())));
public void RegisterComponents()
{
Container
.RegisterType<IClientContext, SharePointOnlineClientContext>(SharePointClientContext.Online.ToString())
.RegisterType<IClientContext, SharePointOnPremiseClientContext>(SharePointClientContext.OnPremise.ToString())
.RegisterType<ITenantRepository, DocumentDbTenantRepository>(SharePointClientContext.Online.ToString())
.RegisterType<ITenantRepository, JsonTenantRepository>(SharePointClientContext.OnPremise.ToString());
}
}
public enum SharePointClientContext
{
Online,
OnPremise
}
class Program
{
static void Main(string[] args)
{
...
bootstrap.RegisterComponents();
var bla = bootstrap.Initialize(typeof(ISharePointManager), SharePointClientContext.Online);
}
}
So, I register my components in MVC, WCF, Console etc. once with RegisterComponents() and initialize them with Initialize().
My question is, if I want to initialize specific named registration at runtime, from e.g. user input, can it be done otherwise as the code presented (with InjectionFactory or similar)?
This code works fine, but I'm not happy with its implementation. I have a feeling that it could be written in RegisterComponents() instead of Initialize() so that it accepts a parameter of some type, but I don't know how to do it.
Or, is maybe my whole concept wrong? If so, what would you suggest? I need to resolve named registration from a parameter that is only known at runtime, regardless of the technology (MVC, WCF, Console, ...).
Thanks!
Instead of doing different registrations, I would do different resolves.
Let's say that you need to inject IClientContext, but you want different implementations depending on a runtime parameter.
I wrote a similiar answer here. Instead of injecting IClientContext, you could inject IClientContextFactory, which would be responsible for returning the correct IClientContext. It's called Strategy Pattern.
public interface IClientContextFactory
{
string Context { get; } // Add context to the interface.
}
public class SharePointOnlineClientContext : IClientContextFactory
{
public string Context
{
get
{
return SharePointClientContext.Online.ToString();
}
}
}
// Factory for resolving IClientContext.
public class ClientContextFactory : IClientContextFactory
{
public IEnumerable<IClientContext> _clientContexts;
public Factory(IClientContext[] clientContexts)
{
_clientContexts = clientContexts;
}
public IClientContext GetClientContext(string parameter)
{
IClientContext clientContext = _clientContexts.FirstOrDefault(x => x.Context == parameter);
return clientContext;
}
}
Register them all, just as you did. But instead of injecting IClientContext you inject IClientContextFactor.
There also another solution where you use a Func-factory. Look at option 3, in this answer. One may argue that this is a wrapper for the service locator-pattern, but I'll leave that discussion for another time.
public class ClientContextFactory : IClientContextFactory
{
private readonly Func<string, IClientContext> _createFunc;
public Factory(Func<string, IClientContext> createFunc)
{
_createFunc = createFunc;
}
public IClientContext CreateClientContext(string writesTo)
{
return _createFunc(writesTo);
}
}
And use named registrations:
container.RegisterType<IClientContext, SharePointOnlineClientContext>(SharePointClientContext.Online.ToString());
container.RegisterType<IClientContext, SharePointOnPremiseClientContext>(SharePointClientContext.OnPremise.ToString());
container.RegisterType<IFactory, Factory>(
new ContainerControlledLifetimeManager(), // Or any other lifetimemanager.
new InjectionConstructor(
new Func<string, IClientContext>(
context => container.Resolve<IClientContext>(context));
Usage:
public class MyService
{
public MyService(IClientContextFactory clientContextFactory)
{
_clientContextFactory = clientContextFactory;
}
public void DoStuff();
{
var myContext = SharePointClientContext.Online.ToString();
IClientContextclientContext = _clientContextFactory.CreateClientContext(myContext);
}
}
Using AutoFixture with the AutoFixture.AutoMoq package, I sometimes find tests that weren't configured to correctly test the thing they meant to test, but the problem was never discovered because of the default (Loose) Mock behavior:
public interface IService
{
bool IsSomethingTrue(int id);
}
void Main()
{
var fixture = new Fixture()
.Customize(new AutoMoqCustomization());
var service = fixture.Freeze<Mock<IService>>();
Console.WriteLine(service.Object.IsSomethingTrue(1)); // false
}
I'd like to make Mocks get created with Strict behavior, so we're forced to call Setup() for the methods we expect to be called. I can do this for each individual mock like this:
fixture.Customize<Mock<IService>>(c => c.FromFactory(() => new Mock<IService>(MockBehavior.Strict)));
But after combing through source code for AutoMoqCustomization() and the various ISpecimenBuilder and other implementations, I'm pretty lost as to the best way to just make all Mocks get initialized with strict behavior. The framework appears to be very flexible and extensible, so I'm sure there's a simple way to do this--I just can't figure out how.
There's no simple built-in feature that will enable you to do something like that, but it shouldn't be that hard to do.
Essentially, you'd need to change MockConstructorQuery so that it invokes the constructor that takes a MockBehavior value, and pass in MockBehavior.Strict.
Now, you can't change that behaviour in MockConstructorQuery, but that class is only some 9-10 lines of code, so you should be able to create a new class that implements IMethodQuery by using MockConstructorQuery as a starting point.
Likewise, you'll also need to create a custom ICustomization that does almost exactly the same as AutoMoqCustomization, with the only exception that it uses your custom IMethodQuery with strict mock configuration instead of MockConstructorQuery. That's another 7 lines of code you'll need to write.
All that said, in my experience, using strict mocks is a bad idea. It'll make your tests brittle, and you'll waste a lot of time mending 'broken' tests. I can only recommend that you don't do this, but now I've warned you; it's your foot.
For those interested, down below you can find #MarkSeemann's reply translated into code. I am pretty sure it does not cover all use cases and it was not heavily tested. But it should be a good starting point.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using Moq;
using Ploeh.AutoFixture;
using Ploeh.AutoFixture.AutoMoq;
using Ploeh.AutoFixture.Kernel;
namespace ConsoleApplication1
{
public class StrictAutoMoqCustomization : ICustomization
{
public StrictAutoMoqCustomization() : this(new MockRelay()) { }
public StrictAutoMoqCustomization(ISpecimenBuilder relay)
{
// TODO Null check params
Relay = relay;
}
public ISpecimenBuilder Relay { get; }
public void Customize(IFixture fixture)
{
// TODO Null check params
fixture.Customizations.Add(new MockPostprocessor(new MethodInvoker(new StrictMockConstructorQuery())));
fixture.ResidueCollectors.Add(Relay);
}
}
public class StrictMockConstructorMethod : IMethod
{
private readonly ConstructorInfo ctor;
private readonly ParameterInfo[] paramInfos;
public StrictMockConstructorMethod(ConstructorInfo ctor, ParameterInfo[] paramInfos)
{
// TODO Null check params
this.ctor = ctor;
this.paramInfos = paramInfos;
}
public IEnumerable<ParameterInfo> Parameters => paramInfos;
public object Invoke(IEnumerable<object> parameters) => ctor.Invoke(parameters?.ToArray() ?? new object[] { });
}
public class StrictMockConstructorQuery : IMethodQuery
{
public IEnumerable<IMethod> SelectMethods(Type type)
{
if (!IsMock(type))
{
return Enumerable.Empty<IMethod>();
}
if (!GetMockedType(type).IsInterface && !IsDelegate(type))
{
return Enumerable.Empty<IMethod>();
}
var ctor = type.GetConstructor(new[] { typeof(MockBehavior) });
return new IMethod[]
{
new StrictMockConstructorMethod(ctor, ctor.GetParameters())
};
}
private static bool IsMock(Type type)
{
return type != null && type.IsGenericType && typeof(Mock<>).IsAssignableFrom(type.GetGenericTypeDefinition()) && !GetMockedType(type).IsGenericParameter;
}
private static Type GetMockedType(Type type)
{
return type.GetGenericArguments().Single();
}
internal static bool IsDelegate(Type type)
{
return typeof(MulticastDelegate).IsAssignableFrom(type.BaseType);
}
}
}
Usage
var fixture = new Fixture().Customize(new StrictAutoMoqCustomization());
here is i am trying to work.
List<MasterEmployee > masterEmployee = new List<MasterEmployee >();
masterEmployee = MasterEmployee.GetAll("123"); //connecting db and returning a list...
foreach (MasterEmployee item in masterEmployee)
{
foreach (Registration reg in item.Registration) //<<<error here...
{
//
}
}
error here:
Error 2 foreach statement cannot operate on variables of type Registration because Registration does not contain a public definition for 'GetEnumerator'
i have a class called MasterEmployee and in it i have a with few props and few methods on it
[Serializable]
public class MasterEmployee
{
//few props omitted ....
protected Registration _registration;
[CopyConstructorIgnore]
public Registration Registration
{
get
{
return _registration;
}
set
{
this._registration = value;
}
}
protected User _user;
[CopyConstructorIgnore]
public User MyUser
{
get
{
return _user;
}
set
{
this._user= value;
}
}
protected Student _student;
[CopyConstructorIgnore]
public Student Student
{
get
{
return _student;
}
set
{
this._student = value;
}
}
}
The explanation provided in the error message is clear enough. You are trying to iterate item.Registration, which is an instance of Registration. However, Registration is not derived from an iterable type, and does not implement the GetEnumerator function required for custom iterable types. So it cannot be iterated using a foreach loop.
But I believe either your naming conventions are incorrect, or you have misunderstood your data model. Why would a Registration instance ever contain a collection of Registration instances? If an item can have multiple Registration instances associated with it, then the property should be called something like item.Registrations, and it should not be of type Registration, it should be a list/collection type that contains Registration instances.
The class should be derived from IEnumerable.
reference and examples: http://msdn.microsoft.com/de-de/library/system.collections.ienumerable%28VS.80%29.aspx
I need to override the call method from NetConnection class, the signature of the method is:
public function call(command:String, responder:Responder, ...parameters):void
How do I override that method?
The following lines didn't work for me.
override public function call(command:String, responder:Responder, ...parameters):void
{
super.call (command, responder, ...parameters);
}
override public function call(command:String, responder:Responder, ...parameters):void
{
super.call (command, responder, parameters);
}
Any clue?
Thanks in advance
parameters is an optional array, so you need to check if they exist.
if(parameters.length > 0) {
super.call(command, responder, parameters);
}
else {
super.call(command, responder);
}
I am modifiying a class method which formats some input paramater dates which are subsequently used as params in a method call into the base class (which lives in another assembly).
I want to verify that the dates i pass in to my method are in the correct format when they are passed to the base class method so i would like to Moq the base class method call. Is this possible with Moq?
As of 2013 with latest Moq you can. Here is an example
public class ViewModelBase
{
public virtual bool IsValid(DateTime date)
{
//some complex shared stuff here
}
}
public class MyViewModel : ViewModelBase
{
public void Save(DateTime date)
{
if (IsValid(date))
{
//do something here
}
}
}
public void MyTest()
{
//arrange
var mockMyViewModel = new Mock<MyViewModel>(){CallBase = true};
mockMyViewModel.Setup(x => x.IsValid(It.IsAny<DateTime>())).Returns(true);
//act
mockMyViewModel.Object.Save();
//assert
//do your assertions here
}
If I understand your question correctly, you have a class A defined in some other assembly, and then an class B implemented more or less like this:
public class B : A
{
public override MyMethod(object input)
{
// Do something
base.MyMethod(input);
}
}
And now you want to verify that base.MyMethod is called?
I don't see how you can do this with a dynamic mock library. All dynamic mock libraries (with the exception of TypeMock) work by dynamically emitting classes that derive from the type in question.
In your case, you can't very well ask Moq to derive from A, since you want to test B.
This means that you must ask Moq to give you a Mock<B>. However, this means that the emitted type derives from B, and while it can override MyMethod (which is still virtual) and call its base (B.MyMethod), it has no way of getting to the original class and verify that B calls base.MyMethod.
Imagine that you have to write a class (C) that derives from B. While you can override MyMethod, there's no way you can verify that B calls A:
public class C : B
{
public override MyMethod(object input)
{
// How to verify that base calls its base?
// base in this context means B, not A
}
}
Again with the possible exception of TypeMock, dynamic mock libraries cannot do anything that you cannot do manually.
However, I would assume that calling the base method you are trying to verify has some observable side effect, so if possible, can you use state-based testing instead of behaviour-based testing to verify the outcome of calling the method?
In any case, state-based testing ought to be your default approach in most cases.
Agree with Mark, it's not possible using Moq.
Depending on your situation you may consider swithcing from inheritance to composition. Then you'll be able to mock the dependency and verify your method. Of course in some cases it just might not worth it.
wrap the base class method in a method and setup that method
e.g.
public class B : A
{
public virtual BaseMyMethod(object input)
{
// Do something
base.MyMethod(input);
}
public override MyMethod(object input)
{
// Do something
BaseMyMethod(input);
}
}
and now Setup the BaseMyMethod
It is quite possible mocking base class. But you will have to modify target class.
For ex. DerivedClass extends BaseClass.
BaseClass has methods MethodA(), MethodB(), MethodC()...
The DerivedClass has this method:
void MyMethod() {
this.MethodA();
this.MethodB();
this.MethodC();
}
You want to mock base class in order to validate that all MethodA(), MethodB(), MethodC() are being called inside MyMethod().
You have to create a field in the DerivedClass:
class DerivedClass {
private BaseClass self = this;
...
}
And also You have to modify the MyMethod():
void MyMethod() {
self.MethodA();
self.MethodB();
self.MethodC();
}
Also add a method, which can inject the this.self field with Mock object
public void setMock(BaseClass mock) {
this.self = mock;
}
Now you can mock:
DerivedClass target = new DerivedClass ();
BaseClass mock = new Mock(typeof(BaseClass));
target.setMock(mock);
target.MyMethod();
mock.verify(MethodA);
mock.verify(MethodB);
mock.verify(MethodC);
Using this technic, you can also mock nested method calls.
I found this solution - ugly but it could work.
var real = new SubCoreClass();
var mock = new Mock<SubCoreClass>();
mock.CallBase = true;
var obj = mock.Object;
mock
.Setup(c => c.Execute())
.Callback(() =>
{
obj.CallBaseMember(typeof(Action), real, "Execute");
Console.WriteLine(obj.GetHashCode());
}
);
public static Delegate CreateBaseCallDelegate(object injectedInstance, Type templateDelegate, object instanceOfBase, string methodName)
{
var deleg = Delegate.CreateDelegate(templateDelegate, instanceOfBase, methodName);
deleg.GetType().BaseType.BaseType.GetField("_target", BindingFlags.Instance | BindingFlags.NonPublic).SetValue(deleg, injectedInstance);
return deleg;
}
public static object CallBaseMember(this object injectedInstance, Type templateDelegate, object instanceOfBase, string methodName, params object[] arguments)
{
return CreateBaseCallDelegate(injectedInstance, templateDelegate, instanceOfBase, methodName).DynamicInvoke(arguments);
}