Override previous setup about moq4 HOT 4 CLOSED

using Moq;
using NUnit.Framework;

[TestFixture]
class TestClass
{
    [Test]
    public void TestMethod()
    {
        var stateConverter = new Mock<StateConverter>();

        var state = new Mock<State>();

        var neightbourSolution1 = new Mock<Solution>();
        var neighbourState1 = new Mock<State>();
        var neightbourSolution2 = new Mock<Solution>();
        var neighbourState2 = new Mock<State>();

        stateConverter.Setup(x => x.FromSolution(neightbourSolution1.Object, It.IsAny<State>()))
            .Returns(neighbourState1.Object);
        stateConverter.Setup(x => x.FromSolution(neightbourSolution2.Object, It.IsAny<State>()))
            .Returns(neighbourState2.Object);

        var state1 = stateConverter.Object.FromSolution(neightbourSolution1.Object, state.Object);//return null ????
        var state2 = stateConverter.Object.FromSolution(neightbourSolution2.Object, state.Object);//return neighbourState2.Object)

        Assert.AreEqual(neighbourState2.Object, state2);//pass test here
        Assert.AreEqual(neighbourState1.Object, state1);//fail here due to null is returned from previous statement
    }
}

public class State
{
}

public class Solution
{
}

public class StateConverter
{
    public virtual object FromSolution(Solution p0, State isAny)
    {
        return null;
    }
}

using Moq;
using NUnit.Framework;

[TestFixture]
class TestClass
{
    [Test]
    public void TestMethod()
    {
        var stateConverter = new Mock<StateConverter>();

        var state = new Mock<State>();

        var neightbourSolution1 = new Mock<Solution>(new object[] { new[] { "foo", "bar" } }) { CallBase = true };
        var neighbourState1 = new Mock<State>();
        var neightbourSolution2 = new Mock<Solution>(new object[] { new[] { "foo", "bar" } }) { CallBase = true };
        var neighbourState2 = new Mock<State>();

        stateConverter.Setup(x => x.FromSolution(neightbourSolution1.Object, It.IsAny<State>()))
            .Returns(neighbourState1.Object);
        stateConverter.Setup(x => x.FromSolution(neightbourSolution2.Object, It.IsAny<State>()))
            .Returns(neighbourState2.Object);

        var state1 = stateConverter.Object.FromSolution(neightbourSolution1.Object, state.Object);//return null ????
        var state2 = stateConverter.Object.FromSolution(neightbourSolution2.Object, state.Object);//return neighbourState2.Object)

        Assert.AreEqual(neighbourState2.Object, state2);//pass test here
        Assert.AreEqual(neighbourState1.Object, state1);//fail here due to null is returned from previous statement
    }
}

public class State
{
}

public class Solution
{
    private string[] _strings;

    public Solution(string[] strings)
    {
        _strings = strings;
    }

    protected bool Equals(Solution other)
    {
        return Equals(_strings, other._strings);
    }

    public override bool Equals(object obj)
    {
        if (ReferenceEquals(null, obj)) return false;
        if (ReferenceEquals(this, obj)) return true;
        if (obj.GetType() != this.GetType()) return false;
        return Equals((Solution)obj);
    }

    public override int GetHashCode()
    {
        return (_strings != null ? _strings.GetHashCode() : 0);
    }
}

public class StateConverter
{
    public virtual object FromSolution(Solution p0, State isAny)
    {
        return null;
    }
}