Adds tests for cardinality and filter aggregations (#23826)

* Adds tests for cardinality and filter aggregations

Relates to #22278

* addresses review comments

1 files changed, 29 insertions, 0 deletions

diff --git a/core/src/main/java/org/elasticsearch/search/aggregations/metrics/cardinality/HyperLogLogPlusPlus.java b/core/src/main/java/org/elasticsearch/search/aggregations/metrics/cardinality/HyperLogLogPlusPlus.java
index 42b4561e07..6425cc3b68 100644
--- a/core/src/main/java/org/elasticsearch/search/aggregations/metrics/cardinality/HyperLogLogPlusPlus.java
+++ b/core/src/main/java/org/elasticsearch/search/aggregations/metrics/cardinality/HyperLogLogPlusPlus.java
@@ -34,6 +34,9 @@ import org.elasticsearch.common.util.IntArray;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
+import java.util.HashSet;
+import java.util.Objects;
+import java.util.Set;
 
 /**
  * Hyperloglog++ counter, implemented based on pseudo code from
@@ -420,6 +423,32 @@ public final class HyperLogLogPlusPlus implements Releasable {
         Releasables.close(runLens, hashSet.sizes);
     }
 
+    private Set<Object> getComparableData(long bucket) {
+        Set<Object> values = new HashSet<>();
+        if (algorithm.get(bucket) == LINEAR_COUNTING) {
+            try (IntArray hashSetValues = hashSet.values(bucket)) {
+                for (long i = 0; i < hashSetValues.size(); i++) {
+                    values.add(hashSetValues.get(i));
+                }
+            }
+        } else {
+            for (long i = 0; i < runLens.size(); i++) {
+                values.add(runLens.get((bucket << p) + i));
+            }
+        }
+        return values;
+    }
+
+    public int hashCode(long bucket) {
+        return Objects.hash(p, algorithm.get(bucket), getComparableData(bucket));
+    }
+
+    public boolean equals(long bucket, HyperLogLogPlusPlus other) {
+        return Objects.equals(p, other.p) &&
+                Objects.equals(algorithm.get(bucket), other.algorithm.get(bucket)) &&
+                Objects.equals(getComparableData(bucket), getComparableData(bucket));
+    }
+
     /**
      * We are actually using HyperLogLog's runLens array but interpreting it as a hash set
      * for linear counting.