Mocking a method that returns a method call to another object

user_10835892 0
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I'm currently unit testing my code and I have problem with creating a mock using Moq. I'm unit testing Foo, and I wish to mock User.GetSomething() to isolate the test. I have created a qick sample of the code that I wish to test:

public class User(){
    public List<int> GetSomething(){
         return bar.CreateList();
     }
}


public class Foo(User user){
   public int SomeMethod() {
      var x = User.GetSomething()
      Do something with x
      ...
    }
}

I have tried creating a mock by doing the following. I have excluded the assert and unnecessary arrange for this question:

var mock = new Mock<User>();
List<int> someList = new List<int>(){1, 2, 3};
mock.Setup(u => u.CreateList()).Returns(SomeList);

Foo(mock.object)
var res = Foo.SomeMethod();
etc.

But I get the exception: System.NotSupportedException : Unsupported expression: u => u.CreateList()

Non-overridable members (here: User.CreateList) may not be used in setup / verification expressions.

moq mocking unit-testing c#
2 Answers

The issue is that, as it says; CreateList is not overrideable, it's not marked virtual and, the input is a concrete (User), and not an interface (IUser).

So to fix this you have 2 options:

  1. Create an IUser interface and use this in your code.
  2. Mark the targeted User methods as virtual
user_24169580

You cannot mock not an overridable methods. In your case, you can change GetSomething() to following: public virtual List<int> GetSomething()

user_77184390
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