Something

using System;
using System.IO;

/// <summary>
/// Summary description for Class1
/// </summary>
/// 

interface ITest
{
    void Boop();
}

public class Test : ITest
{
    public Test()
    {
    }

    public void Boop()
    {
        Console.WriteLine("Bah");
    }
}

public class Meerkat : ITest
{
    public Meerkat()
    {
    }

    public void Boop()
    {
        Console.WriteLine("Bofoffhgfd");
    }
}

public class Class1
{
    public void Go()
    {
        Meerkat test1 = new Meerkat();
        Test test2 = new Test();

        Testy(test1);
        Testy(test2);
    }

	public static void Main()
	{
        new Class1().Go();
	}

    public void Testy(ITest file)
    {
        file.Boop();
    }
}