Fixup reduceRandom tests (#65263)

In aa1ea96b8698aa12bed1c4e8d704882a2a639791 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 @@ public class InternalTopHitsTests extends InternalAggregationTestCase<InternalTo
             usedScores.add(score);
             return score;
         };
+        int requestedSize = between(1, 40);
         Supplier<InternalTopHits> supplier;
         if (randomBoolean()) {
             SortField[] sortFields = randomSortFields();
@@ -96,16 +97,16 @@ public class InternalTopHitsTests extends InternalAggregationTestCase<InternalTo
                 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 @@ public class InternalTopHitsTests extends InternalAggregationTestCase<InternalTo
             sortFieldsComparator(sortFields));
     }
 
-    private InternalTopHits createTestInstanceSortedScore(String name, Map<String, Object> metadata, Supplier<Float> scoreSupplier) {
+    private InternalTopHits createTestInstanceSortedScore(
-        return createTestInstance(name, metadata, scoreSupplier, ScoreDoc::new, TopDocs::new, scoreComparator());
+        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,
+            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 @@ public abstract class InternalAggregationTestCase<T extends InternalAggregation>
     }
 
     @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 @@ public class InternalTopMetricsTests extends InternalAggregationTestCase<Interna
         }
     }
 
+    @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);