diff --git a/org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/instance/InstanceValidatorTests.java b/org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/instance/InstanceValidatorTests.java
index 30294121b..dd57e41e5 100644
--- a/org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/instance/InstanceValidatorTests.java
+++ b/org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/instance/InstanceValidatorTests.java
@@ -23,7 +23,7 @@ class InstanceValidatorTests {
   @Test
   public void testCheckCodeOnServerNoStackLocale() throws InstanceValidator.CheckCodeOnServerException {
       NodeStack stack =mock(NodeStack.class);
-      testCheckCodeOnServer(stack, "ko_KR");
+      testCheckCodeOnServer(stack, "ko-KR");
   }
 
   @Test