Add rolling upgrade test for persistent health node task (#106902)

qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/HealthNodeUpgradeIT.java

@@ -0,0 +1,43 @@
+/*
+ * 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 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 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.upgrades;
+
+import com.carrotsearch.randomizedtesting.annotations.Name;
+
+import org.apache.http.util.EntityUtils;
+import org.elasticsearch.client.Request;
+import org.elasticsearch.client.Response;
+import org.hamcrest.Matchers;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Map;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+
+public class HealthNodeUpgradeIT extends ParameterizedRollingUpgradeTestCase {
+
+    public HealthNodeUpgradeIT(@Name("upgradedNodes") int upgradedNodes) {
+        super(upgradedNodes);
+    }
+
+    public void testHealthNode() throws Exception {
+        if (clusterHasFeature("health.supports_health")) {
+            assertBusy(() -> {
+                Response response = client().performRequest(new Request("GET", "_cat/tasks"));
+                String tasks = EntityUtils.toString(response.getEntity(), StandardCharsets.UTF_8);
+                assertThat(tasks, Matchers.containsString("health-node"));
+            });
+            assertBusy(() -> {
+                Response response = client().performRequest(new Request("GET", "_health_report"));
+                Map<String, Object> health_report = entityAsMap(response.getEntity());
+                assertThat(health_report.get("status"), equalTo("green"));
+            });
+        }
+    }
+}