I have two classes:

public class TestClass1
{
    public int TestInt { get; set; }

    public void TestMethod()
    {
        // Do something
    }
}

public class TestClass2
{
    public int TestInt { get; set; }

    public void TestMethod()
    {
        // Do something
    }
}

I want to create interface that I can use for both classes. The easiest solution is to implement the interface on TestClass1 and TestClass2 but I don;t have access to the implementation of these classes (external dll). I was wondering if I can create new interface and use AutoMapper to map TestClass1 and TestClass2 to ITestInterface:

public interface ITestInterface
{
    int TestInt { get; set; }

    void TestMethod();
}