public void to_date_time()
        {
            Assert.Throws <ArgumentNullException>(() => ConvertExtensions.DateTime(null, new object()));

            Assert.Null(Convert.To.DateTime(null));
            Assert.Equal(DateTime.MinValue, Convert.To.DateTime(DateTime.MinValue));
            Assert.Equal(DateTime.MinValue, Convert.To.DateTime(DateTime.MinValue.ToString(CultureInfo.InvariantCulture)));
            Assert.Null(Convert.To.DateTime(new object()));
        }