internal class Tests
{
    private class TestClass
    {
        internal static void ExecuteSegmentVolume(ILayoutManagementAC mylm)
        {
            var t = mylm.GetActiveViews<ISegmentView>();
            var t1 = mylm.GetActiveViews<IVolumeView>();
        }

        internal static void ExecuteVolumeSegment(ILayoutManagementAC mylm)
        {
            var t1 = mylm.GetActiveViews<IVolumeView>();
            var t = mylm.GetActiveViews<ISegmentView>();
        }
    }

    [Test]
    public void SetupVolumeSegmentExecuteSegmentVolume()
    {
        var layoutAc = new Mock<ILayoutManagementAC>();
        var segmentView = new Mock<ISegmentView>();
        segmentView.As<IVolumeView>();
        var segmentViews = new List<ISegmentView>() { segmentView.Object };

        layoutAc.Setup(x => x.GetActiveViews<IVolumeView>()).Returns(segmentViews.OfType<IVolumeView>());
        layoutAc.Setup(x => x.GetActiveViews<ISegmentView>()).Returns(segmentViews);

        TestClass.ExecuteSegmentVolume(layoutAc.Object);
    }

    [Test]
    public void SetupVolumeSegmentExecuteVolumeSegment()
    {
        var layoutAc = new Mock<ILayoutManagementAC>();
        var segmentView = new Mock<ISegmentView>();
        segmentView.As<IVolumeView>();
        var segmentViews = new List<ISegmentView>() { segmentView.Object };

        layoutAc.Setup(x => x.GetActiveViews<IVolumeView>()).Returns(segmentViews.OfType<IVolumeView>());
        layoutAc.Setup(x => x.GetActiveViews<ISegmentView>()).Returns(segmentViews);

        TestClass.ExecuteVolumeSegment(layoutAc.Object);
    }

    [Test]
    public void SetupSegmentVolumeExecuteSegmentVolume()
    {
        var layoutAc = new Mock<ILayoutManagementAC>();
        var segmentView = new Mock<ISegmentView>();
        segmentView.As<IVolumeView>();
        var segmentViews = new List<ISegmentView>() { segmentView.Object };

        layoutAc.Setup(x => x.GetActiveViews<ISegmentView>()).Returns(segmentViews);
        layoutAc.Setup(x => x.GetActiveViews<IVolumeView>()).Returns(segmentViews.OfType<IVolumeView>());

        TestClass.ExecuteSegmentVolume(layoutAc.Object);
    }

    [Test]
    public void SetupSegmentVolumeExecuteVolumeSegment()
    {
        var layoutAc = new Mock<ILayoutManagementAC>();
        var segmentView = new Mock<ISegmentView>();
        segmentView.As<IVolumeView>();
        var segmentViews = new List<ISegmentView>() { segmentView.Object };

        layoutAc.Setup(x => x.GetActiveViews<ISegmentView>()).Returns(segmentViews);
        layoutAc.Setup(x => x.GetActiveViews<IVolumeView>()).Returns(segmentViews.OfType<IVolumeView>());

        TestClass.ExecuteVolumeSegment(layoutAc.Object);
    }
}

public interface ISegmentView
{
}

public interface IVolumeView : ISegmentView
{
}

public interface ILayoutManagementAC
{
    IEnumerable<T> GetActiveViews<T>() where T : ISegmentView;
}

System.InvalidCastException : Unable to cast object of type 'System.Collections.Generic.List`1[MoqBug.ISegmentView]' to type 'System.Collections.Generic.IEnumerable`1[MoqBug.IVolumeView]'.
   at Castle.Proxies.ILayoutManagementACProxy.GetActiveViews[T]()
   at MoqBug.Tests.TestClass.ExecuteSegmentVolume(ILayoutManagementAC mylm) in E:\Devloping\MoqBug\Tests.cs:line 21
   at MoqBug.Tests.SetupVolumeSegmentExecuteSegmentVolume() in E:\Devloping\MoqBug\Tests.cs:line 42