private static void AssertEqual(object x, object y)
        {
            var comparer = new DataTypeObjectEqualityComparer();

            Assert.IsTrue(comparer.Equals(x, y));
            Assert.AreEqual(comparer.GetHashCode(x), comparer.GetHashCode(y));

            var comparer2 = DataTypeEqualityComparer <object> .Default;

            Assert.IsTrue(comparer2.Equals(x, y));
            Assert.AreEqual(comparer2.GetHashCode(x), comparer2.GetHashCode(y));
        }
        public void DataTypeObjectEqualityComparer_GetHashCode_Null()
        {
            var comparer = new DataTypeObjectEqualityComparer();

            Assert.AreEqual(comparer.GetHashCode(null), EqualityComparer <object> .Default.GetHashCode(null));
        }