add UT coverage

Signed-off-by: Ruirui Zhang <mariazrr@amazon.com>

plugins/workload-management/src/test/java/org/opensearch/plugin/wlm/rest/RestDeleteQueryGroupActionTests.java

@@ -8,15 +8,33 @@
 
 package org.opensearch.plugin.wlm.rest;
 
+import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.CheckedConsumer;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.plugin.wlm.action.DeleteQueryGroupAction;
+import org.opensearch.plugin.wlm.action.DeleteQueryGroupRequest;
+import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.action.RestToXContentListener;
 import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.rest.FakeRestRequest;
 
 import java.util.List;
 
+import org.mockito.ArgumentCaptor;
+
 import static org.opensearch.rest.RestRequest.Method.DELETE;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.doNothing;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
 
 public class RestDeleteQueryGroupActionTests extends OpenSearchTestCase {
-
     /**
      * Test case to validate the construction for RestDeleteQueryGroupAction
      */
@@ -30,4 +48,35 @@ public void testConstruction() {
         assertEquals(DELETE, route.getMethod());
         assertEquals("_wlm/query_group/{name}", route.getPath());
     }
+
+    /**
+     * Test case to validate the prepareRequest logic for RestDeleteQueryGroupAction
+     */
+    @SuppressWarnings("unchecked")
+    public void testPrepareRequest() throws Exception {
+        RestDeleteQueryGroupAction restDeleteQueryGroupAction = new RestDeleteQueryGroupAction();
+        NodeClient nodeClient = mock(NodeClient.class);
+        RestRequest realRequest = new FakeRestRequest();
+        RestRequest spyRequest = spy(realRequest);
+
+        doReturn(TimeValue.timeValueSeconds(30)).when(spyRequest).paramAsTime(eq("cluster_manager_timeout"), any(TimeValue.class));
+        doReturn(TimeValue.timeValueSeconds(60)).when(spyRequest).paramAsTime(eq("timeout"), any(TimeValue.class));
+
+        CheckedConsumer<RestChannel, Exception> consumer = restDeleteQueryGroupAction.prepareRequest(spyRequest, nodeClient);
+        assertNotNull(consumer);
+        ArgumentCaptor<DeleteQueryGroupRequest> requestCaptor = ArgumentCaptor.forClass(DeleteQueryGroupRequest.class);
+        ArgumentCaptor<RestToXContentListener<AcknowledgedResponse>> listenerCaptor = ArgumentCaptor.forClass(RestToXContentListener.class);
+        doNothing().when(nodeClient).execute(eq(DeleteQueryGroupAction.INSTANCE), requestCaptor.capture(), listenerCaptor.capture());
+
+        consumer.accept(mock(RestChannel.class));
+        DeleteQueryGroupRequest capturedRequest = requestCaptor.getValue();
+        assertEquals(null, capturedRequest.getName());
+        assertEquals(TimeValue.timeValueSeconds(30), capturedRequest.clusterManagerNodeTimeout());
+        assertEquals(TimeValue.timeValueSeconds(60), capturedRequest.timeout());
+        verify(nodeClient).execute(
+            eq(DeleteQueryGroupAction.INSTANCE),
+            any(DeleteQueryGroupRequest.class),
+            any(RestToXContentListener.class)
+        );
+    }
 }