How do I mock a class without an interface?

Question

I am working on .NET 4.0 using C# in Windows 7.

I want to test the communication between some methods using mock. The only problem is that I want to do it without i

Answer 1

I think it's better to create an interface for that class. And create a unit test using interface.

If it you don't have access to that class, you can create an adapter for that class.

For example:

public class RealClass
{
    int DoSomething(string input)
    {
        // real implementation here
    }
}

public interface IRealClassAdapter
{
    int DoSomething(string input);
}

public class RealClassAdapter : IRealClassAdapter
{
    readonly RealClass _realClass;

    public RealClassAdapter() => _realClass = new RealClass();

    int DoSomething(string input) => _realClass.DoSomething(input);
}

This way, you can easily create mock for your class using IRealClassAdapter.

Hope it works.