Clarify how to specify scope of replacement class. about ionad HOT 4 CLOSED

using System;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using FodyIonadConsoleApp;

namespace FodyIonadLibraryTests
{
    [TestClass]
    public class UnitTest1
    {
        [TestMethod]
        public void a()
        {
            DateTimeSubstitute.Current = new DateTime(2000, 01, 01, 00, 00, 00);
            var sut = new DateComparer();
            var result = sut.Compare(new DateTime(2000, 01, 01, 00, 05, 00));
            Assert.AreEqual(5, result);
        }

        [TestMethod]
        public void b()
        {
            var result = DateTime.Now;
            Assert.AreEqual(2000, result.Year);
        }
    }
}

using System;

namespace FodyIonadConsoleApp
{
    public class DateComparer
    {
        public double Compare(DateTime dateToCompare)
        {
            return (DateTime.Now - dateToCompare).TotalMinutes;
        }
    }
}

using Ionad;
using System;

namespace FodyIonadLibraryTests
{
    [StaticReplacement(typeof(DateTime))]
    public static class DateTimeSubstitute
    {
        public static DateTime Current { get; set; }

        public static DateTime Now { get { return Current; } }
    }
}