[Backport 2.x] Add tests for RemoteGlobalMetadataManager

server/src/test/java/org/opensearch/gateway/remote/model/RemoteCoordinationMetadataTests.java

@@ -229,7 +229,7 @@ public void testSerDe() throws IOException {
         }
     }
 
-    private CoordinationMetadata getCoordinationMetadata() {
+    public static CoordinationMetadata getCoordinationMetadata() {
         return CoordinationMetadata.builder()
             .term(TERM)
             .lastAcceptedConfiguration(new VotingConfiguration(Set.of("node1")))

server/src/test/java/org/opensearch/gateway/remote/model/RemoteCustomMetadataTests.java

@@ -232,7 +232,7 @@ public void testSerDe() throws IOException {
         }
     }
 
-    private Custom getCustomMetadata() {
+    public static Custom getCustomMetadata() {
         return IndexGraveyard.builder().addTombstone(new Index("test-index", "3q2423")).build();
     }
 

server/src/test/java/org/opensearch/gateway/remote/model/RemoteGlobalMetadataTests.java

@@ -180,7 +180,7 @@ public void testSerDe() throws IOException {
         }
     }
 
-    private Metadata getGlobalMetadata() {
+    public static Metadata getGlobalMetadata() {
         return Metadata.builder()
             .templates(
                 TemplatesMetadata.builder()

server/src/test/java/org/opensearch/gateway/remote/model/RemoteHashesOfConsistentSettingsTests.java

@@ -185,7 +185,7 @@ public void testSerDe() throws IOException {
         }
     }
 
-    private DiffableStringMap getHashesOfConsistentSettings() {
+    public static DiffableStringMap getHashesOfConsistentSettings() {
         Map<String, String> hashesOfConsistentSettings = new HashMap<>();
         hashesOfConsistentSettings.put("secure-setting-key", "secure-setting-value");
         return new DiffableStringMap(hashesOfConsistentSettings);

server/src/test/java/org/opensearch/gateway/remote/model/RemotePersistentSettingsMetadataTests.java

@@ -224,7 +224,7 @@ public void testSerDe() throws IOException {
         }
     }
 
-    private Settings getSettings() {
+    public static Settings getSettings() {
         return Settings.builder().put("random_index_setting_" + randomAlphaOfLength(3), randomAlphaOfLength(5)).build();
     }
 }

server/src/test/java/org/opensearch/gateway/remote/model/RemoteTemplatesMetadataTests.java

@@ -227,7 +227,7 @@ public void testSerDe() throws IOException {
         }
     }
 
-    private TemplatesMetadata getTemplatesMetadata() {
+    public static TemplatesMetadata getTemplatesMetadata() {
         return TemplatesMetadata.builder()
             .put(
                 IndexTemplateMetadata.builder("template" + randomAlphaOfLength(3))

test/framework/src/main/java/org/opensearch/common/util/TestCapturingListener.java

@@ -0,0 +1,39 @@
+/*
+ * 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.common.util;
+
+import org.opensearch.core.action.ActionListener;
+
+/**
+ * A simple implementation of {@link ActionListener} that captures the response and failures used for testing purposes.
+ *
+ * @param <T> the result type
+ */
+public class TestCapturingListener<T> implements ActionListener<T> {
+    private T result;
+    private Exception failure;
+
+    @Override
+    public void onResponse(T result) {
+        this.result = result;
+    }
+
+    @Override
+    public void onFailure(Exception e) {
+        this.failure = e;
+    }
+
+    public T getResult() {
+        return result;
+    }
+
+    public Exception getFailure() {
+        return failure;
+    }
+}