public void GetHashCodeTest()
        {
            var x = new Definition()
            {
                Preface = Guid.NewGuid().ToString(),
                Name = Guid.NewGuid().ToString(),
            };

            var hash = string.Format("{0}{1}", x.Preface, x.Name).GetHashCode();
            var c = new DefinitionComparer();
            Assert.AreEqual(hash, c.GetHashCode(x));
        }
 public void GetHashCodeDefinitionNull()
 {
     var c = new DefinitionComparer();
     c.GetHashCode(null);
 }