addressed comments

Signed-off-by: Junwei Dai <[email protected]>

server/src/main/java/org/opensearch/search/pipeline/TrackingSearchRequestProcessorWrapper.java

@@ -13,6 +13,8 @@
 
 /**
  * Wrapper for SearchRequestProcessor to track execution details.
+ *
+ *  @opensearch.internal
  */
 public class TrackingSearchRequestProcessorWrapper implements SearchRequestProcessor {
 

server/src/main/java/org/opensearch/search/pipeline/TrackingSearchResponseProcessorWrapper.java

@@ -8,8 +8,6 @@
 
 package org.opensearch.search.pipeline;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.core.action.ActionListener;
@@ -18,11 +16,12 @@
 
 /**
  * Wrapper for SearchResponseProcessor to track execution details.
+ *
+ *  @opensearch.internal
  */
 public class TrackingSearchResponseProcessorWrapper implements SearchResponseProcessor {
 
     private final SearchResponseProcessor wrappedProcessor;
-    private static final Logger logger = LogManager.getLogger(TrackingSearchResponseProcessorWrapper.class);
 
     /**
      * Constructor for the wrapper.

server/src/test/java/org/opensearch/search/pipeline/SearchPipelineServiceTests.java

@@ -1828,10 +1828,11 @@ public void testVerbosePipelineWithoutDefinedPipelineThrowsException() {
         SearchRequest searchRequest = new SearchRequest();
         searchRequest.source(SearchSourceBuilder.searchSource().verbosePipeline(true));
 
-        expectThrows(
+        IllegalArgumentException e = expectThrows(
             IllegalArgumentException.class,
             () -> searchPipelineService.resolvePipeline(searchRequest, indexNameExpressionResolver)
         );
+        assertTrue(e.getMessage(), e.getMessage().contains("The 'verbose pipeline' option requires a search pipeline to be defined."));
     }
 
     public void testVerbosePipelineWithRequestProcessorOnly() throws Exception {

server/src/test/java/org/opensearch/search/pipeline/TrackingSearchResponseProcessorWrapperTests.java

@@ -57,6 +57,15 @@ public void testProcessResponse() throws Exception {
         assertEquals(ProcessorExecutionDetail.ProcessorStatus.SUCCESS, detail.getStatus());
     }
 
+    public void testConstructorThrowsExceptionWhenProcessorIsNull() {
+        IllegalArgumentException exception = expectThrows(
+            IllegalArgumentException.class,
+            () -> new TrackingSearchResponseProcessorWrapper(null)
+        );
+
+        assertEquals("Wrapped processor cannot be null.", exception.getMessage());
+    }
+
     public void testProcessResponseAsync() {
         SearchRequest mockRequest = new SearchRequest();
         SearchResponse inputResponse = Mockito.mock(SearchResponse.class);