Mocking Action<>

[Jay]

I am trying to Mock a method that Action<T> delegate. The goal is to mock the Action.Invoke and Assert if the correct value get sent back , but the following code does not seem to work. Any pointers ?

Jay

public interface IClientServerMockingTest

{

    void CallMethod(string id, Action<string> status);

}

[TestClass]

public class ClientServerMockingTest : IClientServerMockingTest

{

    [TestMethod]

    public void TestMethod1()

    {

        var clientServer = Mock.Create<ClientServerMockingTest>();

         var action = Mock.Create<Action<string>>();

         Mock.Arrange(() => clientServer.CallMethod("demo", action)).Raises(() => clientServer.CallMethod("demo", action));

        clientServer.CallMethod("demo", action);    

        Mock.Assert(clientServer);

    }

 

    public void CallMethod(string id, Action<string> action)

    {

        action.Invoke("worked");

    }

}

[Ricky]

Hi Jay,

Thanks again for bringing up the question. However, here are few issues that I found with your test:

1. You are trying to mock a test class itself, which is not an ideal scenario for mocking . Generally, it should be a target class or libraries inside test class.
2. You are creating Mock of an Action delegate which is invalid and you can always write the following:

Mock.Arrange(() => clientServer.CallMethod("demo", Arg.IsAny<Action<string>>()))

Moreover the following line has a recursion, which is telling clientServer.CallMethod to do a self-invocation which can eventually crash the test.

Hope this gives you some sort of pointers.

Kind Regards
Ricky
the Telerik team

[Jay]

Thanks for this, here is how I have got the code so far

[TestClass]
public class TestClass
{
    [TestMethod]
    public void TestMethod1()
    {
        var clientServer = Mock.Create<ClientServerMockingTest>();


        Mock.Arrange(() => clientServer.CallMethod("demo", Arg.IsAny<Action<string>>()));


        Action<string> action = Console.WriteLine;
        clientServer.CallMethod("demo", action);

        Mock.Assert(clientServer);
    }
}

public interface IClientServerMockingTest
{
    void CallMethod(string id, Action<string> status);
}

public class ClientServerMockingTest : IClientServerMockingTest
{
    public void CallMethod(string id, Action<string> status)
    {
        status.Invoke("Worked");
    }
}

what I want to do is Mock the status.invoke so for example instead of the messaged "worked" it will return some thing else we pass.

Thanks

Jay

[Ricky]

Hi Jay,

Thanks again for contacting us. You can write the test using DoInstead that will ensure that Action<string> is invoked as you have mentioned it in Mock.Arrange

[TestMethod]
      public void TestMethod1()
      {
          var clientServer = Mock.Create<ClientServerMockingTest>();

          Mock.Arrange(() => clientServer.CallMethod("demo", Arg.IsAny<Action<string>>())).DoInstead((string id, Action<string> aciton) =>
          {
              aciton.Invoke("faked");
          });

          Action<string> action = Console.WriteLine;

          clientServer.CallMethod("demo", action);

          Mock.Assert(clientServer);
      }

Kind Regards
Mehfuz
the Telerik team