public void ReturnNullIfEntityIdIdentifierIsNull()
        {
            var value = new EntityId();

            var candidate = value.ToIdentifier();
            Assert.IsNull(candidate);
        }
        public void ReturnIdentifierOfEntityId()
        {
            var value = new EntityId { Identifier = new MdmId { Identifier = "A" } };

            var candidate = value.ToIdentifier();
            Assert.AreEqual("A", candidate);
        }