BWC changes and more test cases added

Author: seanzatzdev

server/src/main/java/org/elasticsearch/action/admin/indices/resolve/ResolveIndexFeatures.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+package org.elasticsearch.action.admin.indices.resolve;
+
+import org.elasticsearch.features.FeatureSpecification;
+import org.elasticsearch.features.NodeFeature;
+
+import java.util.Set;
+
+public class ResolveIndexFeatures implements FeatureSpecification {
+
+    // Feature published by nodes that return "mode" in indices.resolve_index responses.
+    public static final NodeFeature RESOLVE_INDEX_RETURNS_MODE = new NodeFeature("resolve_index_returns_mode");
+
+    @Override
+    public Set<NodeFeature> getFeatures() {
+        return Set.of(RESOLVE_INDEX_RETURNS_MODE);
+    }
+
+    @Override
+    public Set<NodeFeature> getTestFeatures() {
+        return Set.of(RESOLVE_INDEX_RETURNS_MODE);
+    }
+
+}