[TEST] Don't assert order of data frame analytics audit messages (elastic#48065)

Audit messages are stored with millisecond timestamps. If two
messages have the same millisecond timestamp then asserting on
their order is impossible given the information available.

This PR changes the assertion on audit messages in the native
data frame analytics tests to assert that the expected audit
messages exist in any order.

Fixes elastic#48035

Author: droberts195

x-pack/plugin/ml/qa/native-multi-node-tests/src/test/java/org/elasticsearch/xpack/ml/integration/MlNativeDataFrameAnalyticsIntegTestCase.java

@@ -32,17 +32,21 @@
 import org.elasticsearch.xpack.core.ml.notifications.AuditorField;
 import org.elasticsearch.xpack.core.ml.utils.PhaseProgress;
 import org.elasticsearch.xpack.ml.dataframe.DataFrameAnalyticsTask;
+import org.hamcrest.Matcher;
+import org.hamcrest.Matchers;
 
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
 
 import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.hasItems;
+import static org.hamcrest.Matchers.hasSize;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.nullValue;
-import static org.hamcrest.Matchers.startsWith;
 
 /**
  * Base class of ML integration tests that use a native data_frame_analytics process
@@ -187,18 +191,16 @@ protected static void assertThatAuditMessagesMatch(String configId, String... ex
         // Since calls to write the AbstractAuditor are sent and forgot (async) we could have returned from the start,
         // finished the job (as this is a very short analytics job), all without the audit being fully written.
         assertBusy(() -> assertTrue(indexExists(AuditorField.NOTIFICATIONS_INDEX)));
+        @SuppressWarnings("unchecked")
+        Matcher<String>[] itemMatchers = Arrays.stream(expectedAuditMessagePrefixes).map(Matchers::startsWith).toArray(Matcher[]::new);
         assertBusy(() -> {
-            String[] actualAuditMessages = fetchAllAuditMessages(configId);
-            assertThat("Messages: " + Arrays.toString(actualAuditMessages), actualAuditMessages.length,
-                equalTo(expectedAuditMessagePrefixes.length));
-            for (int i = 0; i < actualAuditMessages.length; i++) {
-                assertThat(actualAuditMessages[i], startsWith(expectedAuditMessagePrefixes[i]));
-            }
+            final List<String> allAuditMessages = fetchAllAuditMessages(configId);
+            assertThat(allAuditMessages, hasItems(itemMatchers));
+            assertThat("Messages: " + allAuditMessages, allAuditMessages, hasSize(expectedAuditMessagePrefixes.length));
         });
     }
 
-    @SuppressWarnings("unchecked")
-    private static String[] fetchAllAuditMessages(String dataFrameAnalyticsId) throws Exception {
+    private static List<String> fetchAllAuditMessages(String dataFrameAnalyticsId) {
         RefreshRequest refreshRequest = new RefreshRequest(AuditorField.NOTIFICATIONS_INDEX);
         RefreshResponse refreshResponse = client().execute(RefreshAction.INSTANCE, refreshRequest).actionGet();
         assertThat(refreshResponse.getStatus().getStatus(), anyOf(equalTo(200), equalTo(201)));
@@ -212,6 +214,6 @@ private static String[] fetchAllAuditMessages(String dataFrameAnalyticsId) throw
 
         return Arrays.stream(searchResponse.getHits().getHits())
             .map(hit -> (String) hit.getSourceAsMap().get("message"))
-            .toArray(String[]::new);
+            .collect(Collectors.toList());
     }
 }