NIAD-3304: Fix issue with ordering of originalText when mapping to CD XML

* Update `CodeableConceptCdMapper` to only add code translations when it is possible to map from URL to OID as anything other than an OID is not supported in the schema.
* Update CodesSystemsUtil to return empty string if a mapping to known code system cannot be found.
* Update test accordingly.

Author: MartinWheelerMT

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

@@ -1,5 +1,6 @@
 package uk.nhs.adaptors.gp2gp.ehr.mapper;
 
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
@@ -316,12 +317,17 @@ private List<Coding> getNonSnomedCodeCodings(CodeableConcept codeableConcept) {
             .filter(coding -> !isSnomed(coding))
             .toList();
 
+        List<Coding> nonSnomedCodings = new ArrayList<>();
+
         for (Coding coding : nonSnomedCodeCodings) {
             var hl7CodeSystem = CodeSystemsUtil.getHl7code(coding.getSystem());
-            coding.setSystem(hl7CodeSystem);
+            if (!hl7CodeSystem.isEmpty()) {
+                coding.setSystem(hl7CodeSystem);
+                nonSnomedCodings.add(coding);
+            }
         }
 
-        return nonSnomedCodeCodings;
+        return nonSnomedCodings;
     }
 
     private Optional<String> findOriginalText(CodeableConcept codeableConcept, Optional<Coding> coding) {

service/src/main/java/uk/nhs/adaptors/gp2gp/ehr/utils/CodeSystemsUtil.java

@@ -12,10 +12,11 @@ public final class CodeSystemsUtil {
         "http://snomed.info/sct", "2.16.840.1.113883.2.1.3.2.4.15",
         "https://fhir.hl7.org.uk/Id/egton-codes", "2.16.840.1.113883.2.1.6.3",
         "http://read.info/readv2", "2.16.840.1.113883.2.1.6.2",
-        "http://read.info/ctv3", "2.16.840.1.113883.2.1.3.2.4.14"
+        "http://read.info/ctv3", "2.16.840.1.113883.2.1.3.2.4.14",
+        "https://fhir.hl7.org.uk/Id/emis-drug-codes", "2.16.840.1.113883.2.1.6.9"
     );
 
     public static String getHl7code(String fhirCodeSystem) {
-        return SYSTEM_CODES.getOrDefault(fhirCodeSystem, fhirCodeSystem);
+        return SYSTEM_CODES.getOrDefault(fhirCodeSystem, "");
     }
 }

service/src/test/java/uk/nhs/adaptors/gp2gp/utils/CodeSystemUtilTest.java

@@ -17,7 +17,8 @@ private static Stream<Arguments> knownCodeSystems() {
             Arguments.of("http://snomed.info/sct", "2.16.840.1.113883.2.1.3.2.4.15"),
             Arguments.of("https://fhir.hl7.org.uk/Id/egton-codes", "2.16.840.1.113883.2.1.6.3"),
             Arguments.of("http://read.info/readv2", "2.16.840.1.113883.2.1.6.2"),
-            Arguments.of("http://read.info/ctv3", "2.16.840.1.113883.2.1.3.2.4.14")
+            Arguments.of("http://read.info/ctv3", "2.16.840.1.113883.2.1.3.2.4.14"),
+            Arguments.of("https://fhir.hl7.org.uk/Id/emis-drug-codes", "2.16.840.1.113883.2.1.6.9")
         );
     }
 
@@ -30,9 +31,9 @@ void When_FhirCodeSystemIsKnown_Expect_CorrectHl7Code(String fhirCodeSystem, Str
     }
 
     @Test
-    void When_FhirCodeSystemIsUnknown_Expect_FhirCodeSystemIsProvided() {
+    void When_FhirCodeSystemIsUnknown_Expect_EmptyString() {
         var hl7Code = CodeSystemsUtil.getHl7code("https://unknown.code/system");
 
-        assertThat(hl7Code).isEqualTo("https://unknown.code/system");
+        assertThat(hl7Code).isEmpty();
     }
 }