Fix IngestServiceTests.testBulkRequestExecutionWithFailures

The test would previously fail if the randomness led to only a single
indexing request being included in the bulk payload. This change
guarantees multiple indexing requests in order to ensure the batch logic
kicks in.

Also replace some unneeded mocks with real classes.

Signed-off-by: Andrew Ross <andrross@amazon.com>

server/src/test/java/org/opensearch/ingest/IngestServiceTests.java

@@ -78,6 +78,7 @@
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.threadpool.ThreadPool.Names;
+import org.hamcrest.MatcherAssert;
 import org.junit.Before;
 
 import java.nio.charset.StandardCharsets;
@@ -104,15 +105,16 @@
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.emptySet;
+import static org.hamcrest.Matchers.contains;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.hamcrest.Matchers.hasSize;
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.notNullValue;
 import static org.hamcrest.Matchers.nullValue;
 import static org.hamcrest.Matchers.sameInstance;
 import static org.mockito.Mockito.any;
-import static org.mockito.Mockito.anyInt;
 import static org.mockito.Mockito.anyString;
 import static org.mockito.Mockito.argThat;
 import static org.mockito.Mockito.doAnswer;
@@ -1106,27 +1108,23 @@ public void testExecuteFailureWithNestedOnFailure() throws Exception {
         verify(completionHandler, times(1)).accept(Thread.currentThread(), null);
     }
 
-    public void testBulkRequestExecutionWithFailures() throws Exception {
+    public void testBulkRequestExecutionWithFailures() {
         BulkRequest bulkRequest = new BulkRequest();
         String pipelineId = "_id";
 
-        int numRequest = scaledRandomIntBetween(8, 64);
-        int numIndexRequests = 0;
-        for (int i = 0; i < numRequest; i++) {
-            DocWriteRequest request;
+        int numIndexRequests = scaledRandomIntBetween(4, 32);
+        for (int i = 0; i < numIndexRequests; i++) {
+            IndexRequest indexRequest = new IndexRequest("_index").id("_id").setPipeline(pipelineId).setFinalPipeline("_none");
+            indexRequest.source(Requests.INDEX_CONTENT_TYPE, "field1", "value1");
+            bulkRequest.add(indexRequest);
+        }
+        int numOtherRequests = scaledRandomIntBetween(4, 32);
+        for (int i = 0; i < numOtherRequests; i++) {
             if (randomBoolean()) {
-                if (randomBoolean()) {
-                    request = new DeleteRequest("_index", "_id");
-                } else {
-                    request = new UpdateRequest("_index", "_id");
-                }
+                bulkRequest.add(new DeleteRequest("_index", "_id"));
             } else {
-                IndexRequest indexRequest = new IndexRequest("_index").id("_id").setPipeline(pipelineId).setFinalPipeline("_none");
-                indexRequest.source(Requests.INDEX_CONTENT_TYPE, "field1", "value1");
-                request = indexRequest;
-                numIndexRequests++;
+                bulkRequest.add(new UpdateRequest("_index", "_id"));
             }
-            bulkRequest.add(request);
         }
 
         CompoundProcessor processor = mock(CompoundProcessor.class);
@@ -1155,23 +1153,22 @@ public void testBulkRequestExecutionWithFailures() throws Exception {
         clusterState = IngestService.innerPut(putRequest, clusterState);
         ingestService.applyClusterState(new ClusterChangedEvent("", clusterState, previousClusterState));
 
-        @SuppressWarnings("unchecked")
-        BiConsumer<Integer, Exception> requestItemErrorHandler = mock(BiConsumer.class);
-        @SuppressWarnings("unchecked")
-        final BiConsumer<Thread, Exception> completionHandler = mock(BiConsumer.class);
+        final Map<Integer, Exception> errorHandler = new HashMap<>();
+        final Map<Thread, Exception> completionHandler = new HashMap<>();
         ingestService.executeBulkRequest(
-            numRequest,
+            numIndexRequests + numOtherRequests,
             bulkRequest.requests(),
-            requestItemErrorHandler,
-            completionHandler,
+            errorHandler::put,
+            completionHandler::put,
             indexReq -> {},
             Names.WRITE,
             bulkRequest
         );
 
-        verify(requestItemErrorHandler, times(numIndexRequests)).accept(anyInt(), argThat(o -> o.getCause().equals(error)));
+        MatcherAssert.assertThat(errorHandler.entrySet(), hasSize(numIndexRequests));
+        errorHandler.values().forEach(e -> assertEquals(e.getCause(), error));
 
-        verify(completionHandler, times(1)).accept(Thread.currentThread(), null);
+        MatcherAssert.assertThat(completionHandler.keySet(), contains(Thread.currentThread()));
     }
 
     public void testBulkRequestExecution() throws Exception {