Searchable snapshot upgrade compatibility

x-pack/qa/repository-old-versions-compatibility/src/javaRestTest/java/org/elasticsearch/oldrepos/searchablesnapshot/MountFromVersion5IT.java

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+/*
+ * 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; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+package org.elasticsearch.oldrepos.searchablesnapshot;
+
+import org.elasticsearch.test.cluster.util.Version;
+
+public class MountFromVersion5IT extends SearchableSnapshotTestCase {
+
+    public MountFromVersion5IT(Version version) {
+        super(version);
+    }
+
+    public void testSearchableSnapshot() throws Exception {
+        verifyCompatibility("5");
+    }
+}

x-pack/qa/repository-old-versions-compatibility/src/javaRestTest/java/org/elasticsearch/oldrepos/searchablesnapshot/MountFromVersion6IT.java

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+/*
+ * 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; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+package org.elasticsearch.oldrepos.searchablesnapshot;
+
+import org.elasticsearch.test.cluster.util.Version;
+
+public class MountFromVersion6IT extends SearchableSnapshotTestCase {
+
+    public MountFromVersion6IT(Version version) {
+        super(version);
+    }
+
+    public void testSearchableSnapshot() throws Exception {
+        verifyCompatibility("6");
+    }
+}

x-pack/qa/repository-old-versions-compatibility/src/javaRestTest/java/org/elasticsearch/oldrepos/searchablesnapshot/SearchableSnapshotTestCase.java

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+/*
+ * 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; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+package org.elasticsearch.oldrepos.searchablesnapshot;
+
+import org.elasticsearch.client.Request;
+import org.elasticsearch.client.RestClient;
+import org.elasticsearch.common.Strings;
+import org.elasticsearch.oldrepos.AbstractUpgradeCompatibilityTestCase;
+import org.elasticsearch.test.cluster.util.Version;
+
+import static org.elasticsearch.test.rest.ObjectPath.createFromResponse;
+
+/**
+ * Test suite for Archive indices backward compatibility with N-2 versions.
+ * The test suite creates a cluster in the N-1 version, where N is the current version.
+ * Restores snapshots from old-clusters (version 5/6) and upgrades it to the current version.
+ * Test methods are executed after each upgrade.
+ */
+public class SearchableSnapshotTestCase extends AbstractUpgradeCompatibilityTestCase {
+
+    static {
+        clusterConfig = config -> config.setting("xpack.license.self_generated.type", "trial");
+    }
+
+    public SearchableSnapshotTestCase(Version version) {
+        super(version);
+    }
+
+    /**
+     * Overrides the snapshot-restore operation for archive-indices scenario.
+     */
+    @Override
+    public void recover(RestClient client, String repository, String snapshot, String index) throws Exception {
+        var request = new Request("POST", "/_snapshot/" + repository + "/" + snapshot + "/_mount");
+        request.addParameter("wait_for_completion", "true");
+        request.addParameter("storage", "full_copy");
+        request.setJsonEntity(Strings.format("""
+             {
+              "index": "%s",
+              "renamed_index": "%s"
+            }""", index, index));
+        createFromResponse(client.performRequest(request));
+    }
+}