Sample for running a sequence of Do actions for NSubstitute When.Do

DoThese.cs

using System;
using System.Collections.Generic;
using NSubstitute;
using NSubstitute.Core;
using NUnit.Framework;

namespace Sample {
    public static class MyTestExtensions {
        public static void DoThese<T>(this WhenCalled<T> when, params Action<CallInfo>[] actions) {
            var actionQueue = new Queue<Action<CallInfo>>(actions);
            when.Do(x => RunNextAction(x, actionQueue));
        }

        private static void RunNextAction(CallInfo callInfo, Queue<Action<CallInfo>> actions) {
            if (actions.Count == 0) return;
            actions.Dequeue()(callInfo);
        }
    }

    public class DoTheseTests {
        public interface IFoo { void Bar(out string msg); }

        [Test]
        public void SetOutParamToMultipleValues() {
            var foo = Substitute.For<IFoo>();
            string value;
            foo.WhenForAnyArgs(x => x.Bar(out value)).DoThese(x => x[0] = "hi", x => x[0] = "there", x => x[0] = "world");

            foo.Bar(out value);
            Assert.AreEqual("hi", value);
            
            foo.Bar(out value);
            Assert.AreEqual("there", value);

            foo.Bar(out value);
            Assert.AreEqual("world", value);

            foo.Bar(out value);
            Assert.AreEqual("world", value);
        }
    }
}