* Amended test for when Description extension is present with nested display extension when mapping to null flavor codeable concept, to now allow the original text to be taken from the display extension.

* Remove now unneeded function overrides and wrappers which were in place to work around this existing bug.
* Refactor `findOriginalText` to use existing method to retrieve original text

Author: MartinWheelerMT

service/src/main/java/uk/nhs/adaptors/gp2gp/ehr/mapper/CodeableConceptCdMapper.java

@@ -4,7 +4,6 @@
 import java.util.List;
 import java.util.Optional;
 import java.util.function.BiFunction;
-import java.util.function.Function;
 
 import org.apache.commons.lang3.StringUtils;
 import org.hl7.fhir.dstu3.model.AllergyIntolerance;
@@ -153,7 +152,7 @@ public String mapCodeableConceptToCdForBloodPressure(CodeableConcept codeableCon
         var mainCode = getSnomedCodeCoding(codeableConcept);
 
         builder.nullFlavor(mainCode.isEmpty());
-        var originalText = findOriginalTextUsingNestedDisplayExtension(codeableConcept, mainCode);
+        var originalText = findOriginalText(codeableConcept, mainCode);
         originalText.ifPresent(builder::mainOriginalText);
 
         if (mainCode.isPresent()) {
@@ -325,10 +324,7 @@ private List<Coding> getNonSnomedCodeCodings(CodeableConcept codeableConcept) {
         return nonSnomedCodeCodings;
     }
 
-    private Optional<String> findOriginalText(
-        CodeableConcept codeableConcept,
-        Optional<Coding> coding,
-        Function<Coding, Optional<String>> findOriginalTextInDisplayExtension) {
+    private Optional<String> findOriginalText(CodeableConcept codeableConcept, Optional<Coding> coding) {
 
         if (codeableConcept.hasText()) {
             return Optional.ofNullable(codeableConcept.getText());
@@ -339,20 +335,12 @@ private Optional<String> findOriginalText(
                 return getCodingDisplayName(coding.get());
             }
 
-            return findOriginalTextInDisplayExtension.apply(coding.get());
+            return getDisplayTextFromDescriptionExtension(coding.get());
         }
 
         return CodeableConceptMappingUtils.extractTextOrCoding(codeableConcept);
     }
 
-    private Optional<String> findOriginalText(CodeableConcept codeableConcept, Optional<Coding> coding) {
-        return findOriginalText(codeableConcept, coding, codingParameter -> Optional.empty());
-    }
-
-    private Optional<String> findOriginalTextUsingNestedDisplayExtension(CodeableConcept codeableConcept, Optional<Coding> coding) {
-        return findOriginalText(codeableConcept, coding, this::getDisplayTextFromDescriptionExtension);
-    }
-
     private Optional<String> findOriginalTextForAllergy(
         CodeableConcept codeableConcept,
         Optional<Coding> coding,

service/src/test/java/uk/nhs/adaptors/gp2gp/ehr/mapper/CodeableConceptCdMapperTest.java

@@ -488,6 +488,7 @@ void When_WithSnomedCodingNoTextNoDisplayWithDescriptionExtensionWithDisplayExte
 
             var expectedOutput = """
                 <code nullFlavor="UNK">
+                    <originalText>Prothrombin time (observed)</originalText>
                 </code>""";
             var codeableConcept = fhirParseService.parseResource(inputJson, Observation.class).getCode();
 
@@ -508,7 +509,7 @@ void When_WithSnomedCodingNoTextNoDisplayWithNonDescriptionExtension_Expect_Snom
                                 "code": "852471000000107",
                                 "extension": [
                                     {
-                                        "url": "https://fhir.nhs.uk/STU3/StructureDefinition/Extension-coding-sctdescid",
+                                        "url": "https://fhir.nhs.uk/STU3/StructureDefinition/Extension-some-other",
                                         "extension": [
                                             {
                                                 "url": "descriptionDisplay",