diff --git a/org.hl7.fhir.r4/src/test/java/org/hl7/fhir/r4/test/SnapShotGenerationTests.java b/org.hl7.fhir.r4/src/test/java/org/hl7/fhir/r4/test/SnapShotGenerationTests.java
index a730bab4e..5885726b2 100644
--- a/org.hl7.fhir.r4/src/test/java/org/hl7/fhir/r4/test/SnapShotGenerationTests.java
+++ b/org.hl7.fhir.r4/src/test/java/org/hl7/fhir/r4/test/SnapShotGenerationTests.java
@@ -277,6 +277,7 @@ public class SnapShotGenerationTests {
   @Parameters(name = "{index}: file {0}")
   public static Iterable<Object[]> data() throws ParserConfigurationException, IOException, FHIRFormatError {
     SnapShotGenerationTestsContext context = new SnapShotGenerationTestsContext();
+    System.out.println("Snapshot tests using "+TestingUtilities.resourceNameToFile("snapshot-generation-tests.xml"));
     context.tests = (TestScript) new XmlParser().parse(new FileInputStream(TestingUtilities.resourceNameToFile("snapshot-generation-tests.xml")));
 
     context.checkTestsDetails();
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/model/ExpressionNode.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/model/ExpressionNode.java
index 7a4c29f10..c8a66fe1c 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/model/ExpressionNode.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/model/ExpressionNode.java
@@ -61,7 +61,7 @@ public class ExpressionNode {
     
     Empty, Not, Exists, SubsetOf, SupersetOf, IsDistinct, Distinct, Count, Where, Select, All, Repeat, Aggregate, Item /*implicit from name[]*/, As, Is, Single,
     First, Last, Tail, Skip, Take, Union, Combine, Intersect, Exclude, Iif, Upper, Lower, ToChars, Substring, StartsWith, EndsWith, Matches, ReplaceMatches, Contains, Replace, Length,  
-    Children, Descendants, MemberOf, Trace, Today, Now, Resolve, Extension, AllFalse, AnyFalse, AllTrue, AnyTrue,
+    Children, Descendants, MemberOf, Trace, Check, Today, Now, Resolve, Extension, AllFalse, AnyFalse, AllTrue, AnyTrue,
     HasValue, AliasAs, Alias, HtmlChecks, OfType, Type,
     ConvertsToBoolean, ConvertsToInteger, ConvertsToString, ConvertsToDecimal, ConvertsToQuantity, ConvertsToDateTime, ConvertsToTime, ToBoolean, ToInteger, ToString, ToDecimal, ToQuantity, ToDateTime, ToTime, ConformsTo;
 
@@ -108,6 +108,7 @@ public class ExpressionNode {
       if (name.equals("descendants")) return Function.Descendants;
       if (name.equals("memberOf")) return Function.MemberOf;
       if (name.equals("trace")) return Function.Trace;
+      if (name.equals("check")) return Function.Check;
       if (name.equals("today")) return Function.Today;
       if (name.equals("now")) return Function.Now;
       if (name.equals("resolve")) return Function.Resolve;
@@ -183,6 +184,7 @@ public class ExpressionNode {
       case Descendants : return "descendants";
       case MemberOf : return "memberOf";
       case Trace : return "trace";
+      case Check : return "check";
       case Today : return "today";
       case Now : return "now";
       case Resolve : return "resolve";
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/FHIRPathEngine.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/FHIRPathEngine.java
index e8ab0e93a..33fbd220b 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/FHIRPathEngine.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/FHIRPathEngine.java
@@ -1110,6 +1110,7 @@ public class FHIRPathEngine {
     case Descendants: return checkParamCount(lexer, location, exp, 0);
     case MemberOf: return checkParamCount(lexer, location, exp, 1);
     case Trace: return checkParamCount(lexer, location, exp, 1, 2);
+    case Check: return checkParamCount(lexer, location, exp, 2);
     case Today: return checkParamCount(lexer, location, exp, 0);
     case Now: return checkParamCount(lexer, location, exp, 0);
     case Resolve: return checkParamCount(lexer, location, exp, 0);
@@ -2549,6 +2550,10 @@ public class FHIRPathEngine {
       checkParamTypes(exp.getFunction().toCode(), paramTypes, new TypeDetails(CollectionStatus.SINGLETON, TypeDetails.FP_String)); 
       return focus; 
     }
+    case Check : {
+      checkParamTypes(exp.getFunction().toCode(), paramTypes, new TypeDetails(CollectionStatus.SINGLETON, TypeDetails.FP_String)); 
+      return focus; 
+    }
     case Today : 
       return new TypeDetails(CollectionStatus.SINGLETON, TypeDetails.FP_DateTime);
     case Now : 
@@ -2741,6 +2746,7 @@ public class FHIRPathEngine {
     case Descendants : return funcDescendants(context, focus, exp);
     case MemberOf : return funcMemberOf(context, focus, exp);
     case Trace : return funcTrace(context, focus, exp);
+    case Check : return funcCheck(context, focus, exp);
     case Today : return funcToday(context, focus, exp);
     case Now : return funcNow(context, focus, exp);
     case Resolve : return funcResolve(context, focus, exp);
@@ -3484,6 +3490,16 @@ public class FHIRPathEngine {
     return focus;
   }
 
+  private List<Base> funcCheck(ExecutionContext context, List<Base> focus, ExpressionNode exp) throws FHIRException {
+    List<Base> n1 = execute(context, focus, exp.getParameters().get(0), true);
+    if (!convertToBoolean(n1)) {
+      List<Base> n2 = execute(context, focus, exp.getParameters().get(1), true);
+      String name = n2.get(0).primitiveValue();
+      throw new FHIRException("check failed: "+name);
+    }
+    return focus;
+  }
+
   private List<Base> funcDistinct(ExecutionContext context, List<Base> focus, ExpressionNode exp) {
     if (focus.size() <= 1)
       return focus;
diff --git a/org.hl7.fhir.r5/src/main/resources/snapshot-generation-tests.xml b/org.hl7.fhir.r5/src/main/resources/snapshot-generation-tests.xml
index f0ba003aa..f8df40aea 100644
--- a/org.hl7.fhir.r5/src/main/resources/snapshot-generation-tests.xml
+++ b/org.hl7.fhir.r5/src/main/resources/snapshot-generation-tests.xml
@@ -2086,7 +2086,7 @@
         </element>
         <element>
           <path value="Observation.value[x]"/>
-          <sliceName value="quantity"/>
+          <sliceName value="Quantity"/>
           <short value="some text for quantity"/>
           <type>
             <code value="Quantity"/>
@@ -2168,7 +2168,7 @@
         </element>
         <element>
           <path value="Observation.value[x]"/>
-          <sliceName value="quantity"/>
+          <sliceName value="Quantity"/>
           <short value="some text for quantity"/>
           <type>
             <code value="Quantity"/>
@@ -2180,7 +2180,7 @@
         </element>
         <element>
           <path value="Observation.value[x]"/>
-          <sliceName value="codeable"/>
+          <sliceName value="CodeableConcept"/>
           <short value="some text for CodeableConcept"/>
           <type>
             <code value="CodeableConcept"/>
@@ -4310,4 +4310,288 @@
       </assert>
     </action>
   </test>
+
+  <test>
+    <name value="Test40"/>
+    <description value="40. Choice Types: constrain minimum cardinality"/>
+    <action>
+      <operation>
+        <type>
+          <system value="http://hl7.org/fhir/testscript-operation-codes"/>
+          <code value="snapshot"/>
+        </type>
+        <resource value="StructureDefinition"/>
+        <encodeRequestUrl value="false"/>
+        <params value="sort=true"/>
+        <responseId value="t40o"/>
+        <sourceId value="t40"/>
+      </operation>
+    </action>
+    <action>
+      <assert>
+        <label value="test40-1"/>
+        <description value="Snapshot must generate ok"/>
+        <response value="okay"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test40-2"/>
+        <description value="There should only be one element definition for value[x]"/>
+        <direction value="response"/>
+        <expression value="fixture('t40o').snapshot.element.where(path.startsWith('Observation.value')).count() = 1"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test40-3"/>
+        <description value="The element definition for value[x] should have min = 1"/>
+        <direction value="response"/>
+        <expression value="fixture('t40o').snapshot.element.where(path.startsWith('Observation.value')).min = 1"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+  </test>
+  
+  <test>
+    <name value="Test41"/>
+    <description value="41. Choice Types: constrain list of choices to 2"/>
+    <action>
+      <operation>
+        <type>
+          <system value="http://hl7.org/fhir/testscript-operation-codes"/>
+          <code value="snapshot"/>
+        </type>
+        <resource value="StructureDefinition"/>
+        <encodeRequestUrl value="false"/>
+        <params value="sort=true"/>
+        <responseId value="t41o"/>
+        <sourceId value="t41"/>
+      </operation>
+    </action>
+    <action>
+      <assert>
+        <label value="test41-1"/>
+        <description value="Snapshot must generate ok"/>
+        <response value="okay"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test41-2"/>
+        <description value="There should only be one element definition for value[x]"/>
+        <direction value="response"/>
+        <expression value="fixture('t41o').snapshot.element.where(path.startsWith('Observation.value')).count() = 1"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test41-3"/>
+        <description value="The element definition for value[x] should have 2 types"/>
+        <direction value="response"/>
+        <expression value="fixture('t41o').snapshot.element.where(path.startsWith('Observation.value')).type.count() = 2"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+  </test>
+  
+  <test>
+    <name value="Test42"/>
+    <description value="Choice Types: constrain list of choices to 1"/>
+    <action>
+      <operation>
+        <type>
+          <system value="http://hl7.org/fhir/testscript-operation-codes"/>
+          <code value="snapshot"/>
+        </type>
+        <resource value="StructureDefinition"/>
+        <encodeRequestUrl value="false"/>
+        <params value="sort=true"/>
+        <responseId value="t42o"/>
+        <sourceId value="t42"/>
+      </operation>
+    </action>
+    <action>
+      <assert>
+        <label value="test42-1"/>
+        <description value="Snapshot must generate ok"/>
+        <response value="okay"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test42-2"/>
+        <description value="There should only be one element definition for value[x]"/>
+        <direction value="response"/>
+        <expression value="fixture('t42o').snapshot.element.where(path.startsWith('Observation.value')).count() = 1"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test42-3"/>
+        <description value="The element definition for value[x] should have 1 type"/>
+        <direction value="response"/>
+        <expression value="fixture('t42o').snapshot.element.where(path.startsWith('Observation.value')).type.count() = 1"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test42-4"/>
+        <description value="The element definition for value[x] should have short = 'some text'"/>
+        <direction value="response"/>
+        <expression value="fixture('t42o').snapshot.element.where(path.startsWith('Observation.value')).short = 'some text'"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+  </test>
+
+  <test>
+    <name value="Test43"/>
+    <description value="Choice Types: constrain list of choices to 1 and constrain the type (slicing)"/>
+    <action>
+      <operation>
+        <type>
+          <system value="http://hl7.org/fhir/testscript-operation-codes"/>
+          <code value="snapshot"/>
+        </type>
+        <resource value="StructureDefinition"/>
+        <encodeRequestUrl value="false"/>
+        <params value="sort=true"/>
+        <responseId value="t43o"/>
+        <sourceId value="t43"/>
+      </operation>
+    </action>
+    <action>
+      <assert>
+        <label value="test43-1"/>
+        <description value="Snapshot must generate ok"/>
+        <response value="okay"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test43-2"/>
+        <description value="There should be 9 element definitions for value[x] (base + quantity + walking into quantity"/>
+        <direction value="response"/>
+        <expression value="fixture('t43o').snapshot.element.where(path.startsWith('Observation.value')).count() = 9"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test43-3"/>
+        <description value="The element definition for value[x] should have 1 type"/>
+        <direction value="response"/>
+        <expression value="fixture('t43o').snapshot.element.where(id = 'Observation.value[x]').type.count().trace('count') = 1"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test43-4"/>
+        <description value="The element definition for value[x] should have short = 'some text'"/>
+        <direction value="response"/>
+        <expression value="fixture('t43o').snapshot.element.where(id = 'Observation.value[x]').short = 'some text'"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test43-5"/>
+        <description value="The element definition for value[x] quantity slice should have sliceName = 'Quantity'"/>
+        <direction value="response"/>
+        <expression value="fixture('t43o').snapshot.element.where(id = 'Observation.value[x]:Quantity').check(exists(), 'no slice').sliceName = 'Quantity'"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test43-6"/>
+        <description value="The element definition for value[x].value quantity slice should have sliceName = 'Quantity'"/>
+        <direction value="response"/>
+        <expression value="fixture('t43o').snapshot.element.where(id = 'Observation.value[x]:Quantity.value').check(exists(), 'no slice').min = 1"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+  </test>
+  
+  <test>
+    <name value="Test44"/>
+    <description value="Choice Types: constrain list of choices to 1 and constrain the type (shortcut)"/>
+    <action>
+      <operation>
+        <type>
+          <system value="http://hl7.org/fhir/testscript-operation-codes"/>
+          <code value="snapshot"/>
+        </type>
+        <resource value="StructureDefinition"/>
+        <encodeRequestUrl value="false"/>
+        <params value="sort=true"/>
+        <responseId value="t44o"/>
+        <sourceId value="t44"/>
+      </operation>
+    </action>
+    <action>
+      <assert>
+        <label value="test44-1"/>
+        <description value="Snapshot must generate ok"/>
+        <response value="okay"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test44-2"/>
+        <description value="There should be 9 element definitions for value[x] (base + quantity + walking into quantity"/>
+        <direction value="response"/>
+        <expression value="fixture('t44o').snapshot.element.where(path.startsWith('Observation.value')).count() = 9"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test44-3"/>
+        <description value="The element definition for value[x] should have 1 type"/>
+        <direction value="response"/>
+        <expression value="fixture('t44o').snapshot.element.where(id = 'Observation.value[x]').type.count().trace('count') = 1"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test44-4"/>
+        <description value="The element definition for value[x] should have short = 'some text'"/>
+        <direction value="response"/>
+        <expression value="fixture('t44o').snapshot.element.where(id = 'Observation.value[x]').short = 'some text'"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test44-5"/>
+        <description value="The element definition for value[x] quantity slice should have sliceName = 'Quantity'"/>
+        <direction value="response"/>
+        <expression value="fixture('t44o').snapshot.element.where(id = 'Observation.value[x]:Quantity').check(exists(), 'no slice').sliceName = 'Quantity'"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+    <action>
+      <assert>
+        <label value="test44-6"/>
+        <description value="The element definition for value[x].value quantity slice should have sliceName = 'Quantity'"/>
+        <direction value="response"/>
+        <expression value="fixture('t44o').snapshot.element.where(id = 'Observation.value[x]:Quantity.value').check(exists(), 'no slice').min = 1"/>
+        <warningOnly value="false"/>
+      </assert>
+    </action>
+  </test>
+  
 </TestScript>