Add ensureGreen test method for use with adminClient

docs/changelog/113425.yaml

@@ -0,0 +1,5 @@
+pr: 113425
+summary: Add `ensureGreen` test method for use with `adminClient`
+area: Infra/Metrics
+type: enhancement
+issues: []

test/framework/src/main/java/org/elasticsearch/test/rest/ESRestTestCase.java

@@ -1721,7 +1721,11 @@ protected String getEnsureGreenTimeout() {
      * @param index index to test for
      **/
     public final void ensureGreen(String index) throws IOException {
-        ensureHealth(index, (request) -> {
+        ensureGreen(client(), index);
+    }
+
+    public final void ensureGreen(RestClient client, String index) throws IOException {
+        ensureHealth(client, index, (request) -> {
             request.addParameter("wait_for_status", "green");
             request.addParameter("wait_for_no_relocating_shards", "true");
             final String ensureGreenTimeout = getEnsureGreenTimeout();

x-pack/qa/rolling-upgrade-multi-cluster/src/test/java/org/elasticsearch/upgrades/CcrRollingUpgradeIT.java

@@ -405,13 +405,8 @@ private static void resumeIndexFollowing(RestClient client, String followerIndex
         assertOK(client.performRequest(new Request("POST", "/" + followerIndex + "/_ccr/resume_follow")));
     }
 
-    private static void ensureGreen(RestClient client, String index) throws IOException {
-        Request request = new Request("GET", "/_cluster/health/" + index);
-        request.addParameter("wait_for_status", "green");
-        request.addParameter("wait_for_no_relocating_shards", "true");
-        request.addParameter("timeout", "70s");
-        request.addParameter("level", "shards");
-        client.performRequest(request);
+    @Override
+    protected final String getEnsureGreenTimeout() {
+        return "70s";
     }
-
 }