ValueTypeAssertions.cs

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

namespace ValueTypeEquality
{
    [TestClass]
    public class Sample
    {
        [TestMethod]
        public void SampleTest()
        {
            TheType<MyValueType>.ShouldHaveValueEqualitySemantics(() => new MyValueType(4), () => new MyValueType(5));

        }

    }

    public class TheType<T>
    {
        private class NotT
        {
        }

        public static void ShouldHaveValueEqualitySemantics(Func<T> makeA, Func<T> makeB)
        {
            var a = makeA();
            var aPrime = makeA();
            var b = makeB();

            Assert.IsTrue(a.Equals(aPrime));
            Assert.IsTrue(a.GetHashCode().Equals(aPrime.GetHashCode()));
            Assert.IsFalse(a.Equals(b));
            Assert.IsFalse(a.GetHashCode().Equals(b.GetHashCode()));
            Assert.IsFalse(a.Equals(null));
            Assert.IsFalse(a.Equals(new NotT()));
            Assert.AreEqual(a, aPrime);
            Assert.AreNotEqual(a, b);
        }
    }

    public class MyValueType : IEquatable<MyValueType>
    {
        private readonly int _value;

        public MyValueType(int value)
        {
            _value = value;
        }

        public bool Equals(MyValueType other)
        {
            return _value == other._value;
        }

        public override bool Equals(object obj)
        {
            var other = obj as MyValueType;

            if (other == null)
            {
                return false;
            }

            return Equals(other);
        }

        public override int GetHashCode()
        {
            return _value.GetHashCode();
        }
    }

    

}