public void ValueTypeIsNullCondition()
        {
            var isNullCondition = new ValueTypeIsNullCondition <int>
            {
                Value = new FilterValue <int?>
                {
                    LeftValue = 1
                }
            };

            var expr1 = isNullCondition.For <TestSource>(x => x.NullableField);

            Assert.IsFalse(expr1.Compile()(new TestSource {
                NullableField = 1
            }));

            Assert.IsTrue(expr1.Compile()(new TestSource {
                NullableField = null
            }));
        }