Release latch listeners in case of no-op RoutingTableService

server/src/main/java/org/opensearch/cluster/routing/remote/NoopRemoteRoutingTableService.java

@@ -43,7 +43,7 @@ public void getAsyncIndexRoutingWriteAction(
         IndexRoutingTable indexRouting,
         LatchedActionListener<ClusterMetadataManifest.UploadedMetadata> latchedActionListener
     ) {
-        // noop
+        latchedActionListener.onResponse(null);
     }
 
     @Override
@@ -54,7 +54,7 @@ public void getAsyncIndexRoutingDiffWriteAction(
         StringKeyDiffProvider<IndexRoutingTable> routingTableDiff,
         LatchedActionListener<ClusterMetadataManifest.UploadedMetadata> latchedActionListener
     ) {
-        // noop
+        latchedActionListener.onResponse(null);
     }
 
     @Override
@@ -73,7 +73,7 @@ public void getAsyncIndexRoutingReadAction(
         String uploadedFilename,
         LatchedActionListener<IndexRoutingTable> latchedActionListener
     ) {
-        // noop
+        latchedActionListener.onResponse(null);
     }
 
     @Override
@@ -82,7 +82,7 @@ public void getAsyncIndexRoutingTableDiffReadAction(
         String uploadedFilename,
         LatchedActionListener<Diff<RoutingTable>> latchedActionListener
     ) {
-        // noop
+        latchedActionListener.onResponse(null);
     }
 
     @Override

server/src/test/java/org/opensearch/cluster/routing/remote/NoopRemoteRoutingTableServiceTests.java

@@ -0,0 +1,66 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing.remote;
+
+import org.opensearch.action.LatchedActionListener;
+import org.opensearch.cluster.Diff;
+import org.opensearch.cluster.routing.IndexRoutingTable;
+import org.opensearch.cluster.routing.RoutingTable;
+import org.opensearch.common.util.TestCapturingListener;
+import org.opensearch.gateway.remote.ClusterMetadataManifest;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+public class NoopRemoteRoutingTableServiceTests extends OpenSearchTestCase {
+    private NoopRemoteRoutingTableService service;
+
+    @Before
+    public void setup() {
+        service = new NoopRemoteRoutingTableService();
+    }
+
+    public void testGetAsyncIndexRoutingWriteAction() throws InterruptedException {
+        CountDownLatch latch = new CountDownLatch(1);
+        TestCapturingListener<ClusterMetadataManifest.UploadedMetadata> capturingListener = new TestCapturingListener<>();
+        LatchedActionListener<ClusterMetadataManifest.UploadedMetadata> listener = new LatchedActionListener<>(capturingListener, latch);
+        service.getAsyncIndexRoutingWriteAction("clusterUUID", 1, 1, null, listener);
+        latch.await(100, TimeUnit.MILLISECONDS);
+        assertNull(capturingListener.getResult());
+    }
+
+    public void testGetAsyncIndexRoutingReadAction() throws InterruptedException {
+        CountDownLatch latch = new CountDownLatch(1);
+        TestCapturingListener<IndexRoutingTable> capturingListener = new TestCapturingListener<>();
+        LatchedActionListener<IndexRoutingTable> listener = new LatchedActionListener<>(capturingListener, latch);
+        service.getAsyncIndexRoutingReadAction("clusterUUID", "filename", listener);
+        latch.await(100, TimeUnit.MILLISECONDS);
+        assertNull(capturingListener.getResult());
+    }
+
+    public void testGetAsyncIndexRoutingDiffWriteAction() throws InterruptedException {
+        CountDownLatch latch = new CountDownLatch(1);
+        TestCapturingListener<ClusterMetadataManifest.UploadedMetadata> capturingListener = new TestCapturingListener<>();
+        LatchedActionListener<ClusterMetadataManifest.UploadedMetadata> listener = new LatchedActionListener<>(capturingListener, latch);
+        service.getAsyncIndexRoutingDiffWriteAction("clusterUUID", 1, 1, null, listener);
+        latch.await(100, TimeUnit.MILLISECONDS);
+        assertNull(capturingListener.getResult());
+    }
+
+    public void testGetAsyncIndexRoutingDiffReadAction() throws InterruptedException {
+        CountDownLatch latch = new CountDownLatch(1);
+        TestCapturingListener<Diff<RoutingTable>> capturingListener = new TestCapturingListener<>();
+        LatchedActionListener<Diff<RoutingTable>> listener = new LatchedActionListener<>(capturingListener, latch);
+        service.getAsyncIndexRoutingTableDiffReadAction("clusterUUID", "filename", listener);
+        latch.await(100, TimeUnit.MILLISECONDS);
+        assertNull(capturingListener.getResult());
+    }
+}