public void TestValueValidation()
        {
            var ed = new ElementDefinition
            {
                Binding = new ElementDefinition.BindingComponent
                {
                    Strength = BindingStrength.Required,
                    ValueSet = new ResourceReference("http://hl7.org/fhir/ValueSet/data-absent-reason")
                }
            };

            // Non-bindeable things should succeed
            Element v   = new FhirBoolean(true);
            var     nav = new PocoNavigator(v);

            Assert.True(_validator.ValidateBinding(ed, nav).Success);

            v   = new Quantity(4.0m, "masked", "http://hl7.org/fhir/data-absent-reason"); // nonsense, but hey UCUM is not provided with the spec
            nav = new PocoNavigator(v);
            Assert.True(_validator.ValidateBinding(ed, nav).Success);

            v   = new Quantity(4.0m, "maskedx", "http://hl7.org/fhir/data-absent-reason"); // nonsense, but hey UCUM is not provided with the spec
            nav = new PocoNavigator(v);
            Assert.False(_validator.ValidateBinding(ed, nav).Success);

            v   = new Quantity(4.0m, "kg"); // sorry, UCUM is not provided with the spec - still validate against data-absent-reason
            nav = new PocoNavigator(v);
            Assert.False(_validator.ValidateBinding(ed, nav).Success);

            v   = new FhirString("masked");
            nav = new PocoNavigator(v);
            Assert.True(_validator.ValidateBinding(ed, nav).Success);

            v   = new FhirString("maskedx");
            nav = new PocoNavigator(v);
            Assert.False(_validator.ValidateBinding(ed, nav).Success);

            var ic  = new Coding("http://hl7.org/fhir/data-absent-reason", "masked");
            var ext = new Extension {
                Value = ic
            };

            nav = new PocoNavigator(ext);
            Assert.True(_validator.ValidateBinding(ed, nav).Success);

            ic.Code = "maskedx";
            nav     = new PocoNavigator(ext);
            Assert.False(_validator.ValidateBinding(ed, nav).Success);
        }