using System;

using System.Text;

using Autofac.Extras.FakeItEasy;

using FakeItEasy;

public class Program

{

    public interface IStringService

    {

        string GetString(); 

    }

    public static void Main()

    {

        ACallTo_before_Provide();  // outputs ""

        Provide_before_ACallTo();  // outputs "Test string"

    }

    public static void ACallTo_before_Provide()

    {

        using (var fake = new AutoFake())

        {

            A.CallTo(() => fake.Resolve<IStringService>().GetString())

                .Returns("Test string");

​

            fake.Provide(new StringBuilder());

            var stringService = fake.Resolve<IStringService>();

            string result = stringService.GetString();

​

            // result should be "Test string", but instead it's an empty string.

            Console.WriteLine($"ACallTo_before_Provide(): result = \"{result}\"");

        }

    }

    public static void Provide_before_ACallTo()

    {

        // Same code as above, but with the calls to fake.Provide<T>() and A.CallTo() swapped

        using (var fake = new AutoFake())

        {

            fake.Provide(new StringBuilder());

            A.CallTo(() => fake.Resolve<IStringService>().GetString())

                .Returns("Test string");

            var stringService = fake.Resolve<IStringService>();

            string result = stringService.GetString();

​

            // This time, the result is "Test string" as expected

            Console.WriteLine($"Provide_before_ACallTo(): result = \"{result}\"");

        }

    }

}

​