diff --git a/src/test/kotlin/org/opensearch/indexmanagement/indexstatemanagement/IndexStateManagementRestTestCase.kt b/src/test/kotlin/org/opensearch/indexmanagement/indexstatemanagement/IndexStateManagementRestTestCase.kt
index b938f45c7..ab8e772a2 100644
--- a/src/test/kotlin/org/opensearch/indexmanagement/indexstatemanagement/IndexStateManagementRestTestCase.kt
+++ b/src/test/kotlin/org/opensearch/indexmanagement/indexstatemanagement/IndexStateManagementRestTestCase.kt
@@ -474,7 +474,7 @@ abstract class IndexStateManagementRestTestCase : IndexManagementRestTestCase()
 
     protected fun ManagedIndexConfig.toHttpEntity(): HttpEntity = StringEntity(toJsonString(), APPLICATION_JSON)
 
-    protected fun ExplainFilter.toHttpEntity(): HttpEntity = StringEntity(toJsonString(), ContentType.APPLICATION_JSON)
+    protected fun ExplainFilter.toHttpEntity(): HttpEntity = StringEntity(toJsonString(), APPLICATION_JSON)
 
     protected fun ChangePolicy.toHttpEntity(): HttpEntity {
         var string = "{\"${ChangePolicy.POLICY_ID_FIELD}\":\"$policyID\","