Make ConfigurationTests.test20HostnameSubstitution more resilient (el…

…astic#111216)

This is an attempt to fix occasional test failures where asserting on a
request response fails because the cluster has not finished
initialization and cannot yet serve requests.

Closes elastic#109660

qa/packaging/src/test/java/org/elasticsearch/packaging/test/ConfigurationTests.java

@@ -20,7 +20,6 @@
 
 import static java.nio.file.attribute.PosixFilePermissions.fromString;
 import static org.elasticsearch.packaging.util.FileUtils.append;
-import static org.hamcrest.Matchers.equalTo;
 import static org.junit.Assume.assumeFalse;
 
 public class ConfigurationTests extends PackagingTestCase {
@@ -50,13 +49,15 @@ public void test20HostnameSubstitution() throws Exception {
             // security auto-config requires that the archive owner and the node process user be the same
             Platforms.onWindows(() -> sh.chown(confPath, installation.getOwner()));
             assertWhileRunning(() -> {
-                final String nameResponse = ServerUtils.makeRequest(
-                    Request.Get("https://localhost:9200/_cat/nodes?h=name"),
-                    "test_superuser",
-                    "test_superuser_password",
-                    ServerUtils.getCaCert(confPath)
-                ).strip();
-                assertThat(nameResponse, equalTo("mytesthost"));
+                assertBusy(() -> {
+                    final String nameResponse = ServerUtils.makeRequest(
+                        Request.Get("https://localhost:9200/_cat/nodes?h=name"),
+                        "test_superuser",
+                        "test_superuser_password",
+                        ServerUtils.getCaCert(confPath)
+                    ).strip();
+                    assertEquals("mytesthost", nameResponse);
+                });
             });
             Platforms.onWindows(() -> sh.chown(confPath));
         });