Added new txt-1 and txt-2 validation components

src/Firely.Fhir.Validation.Compilation.Shared/SchemaBuilders/FhirPathBuilder.cs

@@ -50,6 +50,8 @@ public IEnumerable<IAssertion> Build(ElementDefinitionNavigator nav, ElementConv
         {
             "ele-1" => new FhirEle1Validator(),
             "ext-1" => new FhirExt1Validator(),
+            "txt-1" => new FhirTxt1Validator(),
+            "txt-2" => new FhirTxt2Validator(),
             _ => null
         };
     }

src/Firely.Fhir.Validation/Impl/FhirTxt1Validator.cs

@@ -0,0 +1,68 @@
+/* 
+ * Copyright (C) 2022, Firely (info@fire.ly) - All Rights Reserved
+ * Proprietary and confidential. Unauthorized copying of this file, 
+ * via any medium is strictly prohibited.
+ */
+
+using Hl7.Fhir.ElementModel;
+using Hl7.Fhir.Model;
+using Hl7.Fhir.Support;
+using Newtonsoft.Json.Linq;
+using System.Linq;
+using System.Runtime.Serialization;
+
+namespace Firely.Fhir.Validation
+{
+    /// <summary>
+    /// Represents the hand-coded version of the equivalent <see cref="FhirPathValidator"/> running invariant "ext-1".
+    /// </summary>
+    [DataContract]
+    public class FhirTxt1Validator : InvariantValidator
+    {
+        /// <inheritdoc/>
+        public override string Key => "txt-1";
+
+        /// <inheritdoc/>
+        public override OperationOutcome.IssueSeverity? Severity => OperationOutcome.IssueSeverity.Error;
+
+        /// <inheritdoc/>
+        public override bool BestPractice => false;
+
+        /// <inheritdoc/>
+        public override string? HumanDescription => "The narrative SHALL contain only the basic html formatting elements and attributes described in chapters 7-11 (except section 4 of chapter 9) and 15 of the HTML 4.0 standard, <a> elements (either name or href), images and internally contained style attributes";
+
+        /// <inheritdoc/>
+        protected override (bool, ResultReport?) RunInvariant(ITypedElement input, ValidationContext vc, ValidationState _)
+        {
+            // Original expression:   "expression": "htmlChecks()"
+
+            if (input.Value is null) return (false, null);
+
+            switch (input.Value)
+            {
+                case string value:
+                    {
+                        var result = XHtml.IsValidNarrativeXhtml(input.Value.ToString(), out var errors);
+
+                        if (result)
+                        {
+                            return (true, null);
+                        }
+                        else
+                        {
+                            var issues = errors.Select(e => new IssueAssertion(Issue.XSD_VALIDATION_ERROR, e));
+                            return (false, new ResultReport(ValidationResult.Failure, issues));
+                        }
+                    }
+                default:
+                    return (false, new ResultReport(ValidationResult.Failure, 
+                                                    new IssueAssertion(Issue.CONTENT_ELEMENT_INVALID_PRIMITIVE_VALUE,
+                                                    $"Narrative should be of type string, but is of type ({input.Value.GetType()})")));
+
+            }           
+        }
+
+        /// <inheritdoc/>
+        public override JToken ToJson() => new JProperty("FastInvariant-txt1", new JObject());
+    }
+}

src/Firely.Fhir.Validation/Impl/FhirTxt2Validator.cs

@@ -0,0 +1,42 @@
+/* 
+ * Copyright (C) 2022, Firely (info@fire.ly) - All Rights Reserved
+ * Proprietary and confidential. Unauthorized copying of this file, 
+ * via any medium is strictly prohibited.
+ */
+
+using Hl7.Fhir.ElementModel;
+using Hl7.Fhir.Model;
+using Newtonsoft.Json.Linq;
+using System.Runtime.Serialization;
+
+namespace Firely.Fhir.Validation
+{
+    /// <summary>
+    /// Represents the hand-coded version of the equivalent <see cref="FhirPathValidator"/> running invariant "ext-1".
+    /// </summary>
+    [DataContract]
+    public class FhirTxt2Validator : InvariantValidator
+    {
+        /// <inheritdoc/>
+        public override string Key => "txt-2";
+
+        /// <inheritdoc/>
+        public override OperationOutcome.IssueSeverity? Severity => OperationOutcome.IssueSeverity.Error;
+
+        /// <inheritdoc/>
+        public override bool BestPractice => false;
+
+        /// <inheritdoc/>
+        public override string? HumanDescription => "The narrative SHALL have some non-whitespace content";
+
+        /// <inheritdoc/>
+        protected override (bool, ResultReport?) RunInvariant(ITypedElement input, ValidationContext vc, ValidationState _)
+        {
+            //Check whether the narrative contains non-whitespace content.
+            return (!string.IsNullOrWhiteSpace(input.Value.ToString()), null);
+        }
+
+        /// <inheritdoc/>
+        public override JToken ToJson() => new JProperty("FastInvariant-txt2", new JObject());
+    }
+}

test/Firely.Fhir.Validation.Compilation.Tests.Shared/SchemaBuilders/FhirPathBuilderTests.cs

@@ -53,7 +53,15 @@ public void HandcodedFPConstraintsTest()
                     new()
                     {
                         Key = "ext-1"
-                    }
+                    },
+                    new()
+                    {
+                        Key = "txt-1"
+                    },
+                    new()
+                    {
+                        Key = "txt-2"
+                    },
 
                 }
             };
@@ -62,11 +70,13 @@ public void HandcodedFPConstraintsTest()
 
             var result = _sut.Build(nav, ElementConversionMode.Full);
             var builders = result.Should()
-                .HaveCount(2).And
+                .HaveCount(4).And
                 .AllBeAssignableTo<InvariantValidator>().Which;
 
             builders.First().Should().BeOfType<FhirEle1Validator>();
             builders.Skip(1).First().Should().BeOfType<FhirExt1Validator>();
+            builders.Skip(2).First().Should().BeOfType<FhirTxt1Validator>();
+            builders.Skip(3).First().Should().BeOfType<FhirTxt2Validator>();
         }
 
         [TestMethod]

test/Firely.Fhir.Validation.Compilation.Tests.Shared/SimpleValidationsTests.cs

@@ -166,6 +166,31 @@ public void ValidateExtensionCardinality()
             results = patientSchema!.Validate(patient.ToTypedElement(), _fixture.NewValidationContext());
             results.IsSuccessful.Should().Be(true, because: "extensions have the correct cardinality");
         }
+
+        [Fact]
+        public void ValidateNarrativeInvariants()
+        {
+            var justWhiteSpace = new Narrative
+            {
+                Status = Narrative.NarrativeStatus.Additional,
+                Div = " "
+            };
+
+            var invalidHtml = new Narrative
+            {
+                Status = Narrative.NarrativeStatus.Additional,
+                Div = "<div xmlns=\"http://www.w3.org/1999/xhtml\"><script> document.getElementById(\"demo\").innerHTML = \"Hello JavaScript!\"; </script></div>"
+            };
+
+            var narrativeSchema = _fixture.SchemaResolver.GetSchema("http://hl7.org/fhir/StructureDefinition/Narrative");
+
+            var results = narrativeSchema!.Validate(justWhiteSpace.ToTypedElement(), _fixture.NewValidationContext());
+            results.IsSuccessful.Should().Be(false, "Instance failed constraint txt-2 \"The narrative SHALL have some non-whitespace content\"");
+
+            results = narrativeSchema!.Validate(invalidHtml.ToTypedElement(), _fixture.NewValidationContext());
+            results.IsSuccessful.Should().Be(false, "The element 'div' in namespace 'http://www.w3.org/1999/xhtml' has invalid child element 'script' in namespace 'http://www.w3.org/1999/xhtml'. List of possible elements expected: 'p, h1, h2, h3, h4, h5, h6, div, ul, ol, dl, pre, hr, blockquote, address, table, a, br, span, bdo, map, img, tt, i, b, big, small, em, strong, dfn, code, q, samp, kbd, var, cite, abbr, acronym, sub, sup' in namespace 'http://www.w3.org/1999/xhtml'.");
+
+        }
     }
 }