Add xversion validation test cases

validator/device-r4.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Device xmlns="http://hl7.org/fhir">
+
+
+  <!-- defined in R5 but not R4-->
+  <extension url="http://hl7.org/fhir/5.0/StructureDefinition/extension-Device.availabilityStatus">
+    <valueCodeableConcept>
+      <coding>
+        <system value="http://hl7.org/fhir/device-availability-status"/>
+        <code value="damaged"/>
+      </coding>
+    </valueCodeableConcept>
+  </extension>  
+
+  <!-- unknown is valid in R4, but not R5-->
+  <status value="unknown"/>
+
+  <!-- device status reason is defined in R4, but not R5. Although it has a THO URL, it was never in THO -->
+  <statusReason>
+    <coding>
+      <system value="http://terminology.hl7.org/CodeSystem/device-status-reason"/>
+      <code value=""/>
+    </coding>
+  </statusReason>
+</Device>

validator/device-r5.xml

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Device xmlns="http://hl7.org/fhir">
+  <!-- device status reason is defined in R4, but not R5. Although it has a THO URL, it was never in THO -->
+  <extension url="http://hl7.org/fhir/4.0/StructureDefinition/extension-Device.statusReason">
+    <valueCodeableConcept>
+      <coding>
+        <system value="http://terminology.hl7.org/CodeSystem/device-status-reason"/>
+        <code value=""/>
+      </coding>
+    </valueCodeableConcept>
+  </extension>
+
+  <!-- unknown is valid in R4, but not R5-->
+  <status>
+    <extension url="http://hl7.org/fhir/4.0/StructureDefinition/extension-Device.status">
+      <valueCode value="unknown"/>
+    </extension>
+  </status>
+
+  <!-- defined in R5 but not R4-->
+  <availabilityStatus>
+    <coding>
+      <system value="http://hl7.org/fhir/device-availability-status"/>
+      <code value="damaged"/>
+    </coding>
+  </availabilityStatus>
+
+</Device>