Fixup reduceRandom tests (#65263)

In aa1ea96 I made all
`testReduceRandom` tests for aggs mimick production more precisely.
More precisely, they pick the correct "lead" result when performing
partial reduction. This is great, but, sadly, some tests assumed that we
always reduced against the "first" aggregator. This fixes those tests.

Closes #65163

server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalTopHitsTests.java

@@ -69,10 +69,10 @@ public class InternalTopHitsTests extends InternalAggregationTestCase<InternalTo
     @Override
     protected InternalTopHits createTestInstance(String name, Map<String, Object> metadata) {
         if (randomBoolean()) {
-            return createTestInstanceSortedByFields(name, metadata, ESTestCase::randomFloat,
+            return createTestInstanceSortedByFields(name, between(1, 40), metadata, ESTestCase::randomFloat,
                 randomSortFields(), InternalTopHitsTests::randomOfType);
         }
-        return createTestInstanceSortedScore(name, metadata, ESTestCase::randomFloat);
+        return createTestInstanceSortedScore(name, between(1, 40), metadata, ESTestCase::randomFloat);
     }
 
     @Override
@@ -87,6 +87,7 @@ protected List<InternalTopHits> randomResultsToReduce(String name, int size) {
             usedScores.add(score);
             return score;
         };
+        int requestedSize = between(1, 40);
         Supplier<InternalTopHits> supplier;
         if (randomBoolean()) {
             SortField[] sortFields = randomSortFields();
@@ -96,16 +97,16 @@ protected List<InternalTopHits> randomResultsToReduce(String name, int size) {
                 usedSortFieldValues.add(value);
                 return value;
             };
-            supplier = () -> createTestInstanceSortedByFields(name, null, scoreSupplier, sortFields, sortFieldValueSuppier);
+            supplier = () -> createTestInstanceSortedByFields(name, requestedSize, null, scoreSupplier, sortFields, sortFieldValueSuppier);
         } else {
-            supplier = () -> createTestInstanceSortedScore(name, null, scoreSupplier);
+            supplier = () -> createTestInstanceSortedScore(name, requestedSize, null, scoreSupplier);
         }
         return Stream.generate(supplier).limit(size).collect(toList());
     }
 
-    private InternalTopHits createTestInstanceSortedByFields(String name, Map<String, Object> metadata,
+    private InternalTopHits createTestInstanceSortedByFields(String name, int requestedSize, Map<String, Object> metadata,
             Supplier<Float> scoreSupplier, SortField[] sortFields, Function<SortField.Type, Object> sortFieldValueSupplier) {
-        return createTestInstance(name, metadata, scoreSupplier,
+        return createTestInstance(name, metadata, scoreSupplier, requestedSize,
             (docId, score) -> {
                 Object[] fields = new Object[sortFields.length];
                 for (int f = 0; f < sortFields.length; f++) {
@@ -118,15 +119,20 @@ private InternalTopHits createTestInstanceSortedByFields(String name, Map<String
             sortFieldsComparator(sortFields));
     }
 
-    private InternalTopHits createTestInstanceSortedScore(String name, Map<String, Object> metadata, Supplier<Float> scoreSupplier) {
-        return createTestInstance(name, metadata, scoreSupplier, ScoreDoc::new, TopDocs::new, scoreComparator());
+    private InternalTopHits createTestInstanceSortedScore(
+        String name,
+        int requestedSize,
+        Map<String, Object> metadata,
+        Supplier<Float> scoreSupplier
+    ) {
+        return createTestInstance(name, metadata, scoreSupplier, requestedSize, ScoreDoc::new, TopDocs::new, scoreComparator());
     }
 
-    private InternalTopHits createTestInstance(String name, Map<String, Object> metadata, Supplier<Float> scoreSupplier, 
+    private InternalTopHits createTestInstance(String name, Map<String, Object> metadata, Supplier<Float> scoreSupplier,
+            int requestedSize,
             BiFunction<Integer, Float, ScoreDoc> docBuilder,
             BiFunction<TotalHits, ScoreDoc[], TopDocs> topDocsBuilder, Comparator<ScoreDoc> comparator) {
         int from = 0;
-        int requestedSize = between(1, 40);
         int actualSize = between(0, requestedSize);
 
         float maxScore = Float.NEGATIVE_INFINITY;

test/framework/src/main/java/org/elasticsearch/test/InternalAggregationTestCase.java

@@ -338,7 +338,6 @@ protected T createUnmappedInstance(String name, Map<String, Object> metadata) {
     }
 
     @Override
-
     protected final Class<T> categoryClass() {
         return (Class<T>) InternalAggregation.class;
     }

x-pack/plugin/analytics/src/test/java/org/elasticsearch/xpack/analytics/topmetrics/InternalTopMetricsTests.java

@@ -331,6 +331,27 @@ protected void assertFromXContent(InternalTopMetrics aggregation, ParsedAggregat
         }
     }
 
+    @Override
+    protected List<InternalTopMetrics> randomResultsToReduce(String name, int count) {
+        InternalTopMetrics prototype = createTestInstance();
+        return randomList(
+            count,
+            count,
+            () -> new InternalTopMetrics(
+                prototype.getName(),
+                prototype.getSortOrder(),
+                prototype.getMetricNames(),
+                prototype.getSize(),
+                randomTopMetrics(
+                    InternalAggregationTestCase::randomNumericDocValueFormat,
+                    between(0, prototype.getSize()),
+                    prototype.getMetricNames().size()
+                ),
+                prototype.getMetadata()
+            )
+        );
+    }
+
     @Override
     protected void assertReduced(InternalTopMetrics reduced, List<InternalTopMetrics> inputs) {
         InternalTopMetrics first = inputs.get(0);