[Tests] Add unit tests for InternalFilters (#24624)

Relates to #22278

core/src/main/java/org/elasticsearch/search/aggregations/bucket/filters/InternalFilters.java

@@ -33,6 +33,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 public class InternalFilters extends InternalMultiBucketAggregation<InternalFilters, InternalFilters.InternalBucket> implements Filters {
     public static class InternalBucket extends InternalMultiBucketAggregation.InternalBucket implements Filters.Bucket {
@@ -113,13 +114,35 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.endObject();
             return builder;
         }
+
+        @Override
+        public boolean equals(Object other) {
+            if (this == other) {
+                return true;
+            }
+            if (other == null || getClass() != other.getClass()) {
+                return false;
+            }
+            InternalBucket that = (InternalBucket) other;
+            return Objects.equals(key, that.key)
+                    && Objects.equals(keyed,  keyed)
+                    && Objects.equals(docCount, that.docCount)
+                    && Objects.equals(aggregations, that.aggregations);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(getClass(), key, keyed, docCount, aggregations);
+        }
     }
 
     private final List<InternalBucket> buckets;
     private final boolean keyed;
-    private Map<String, InternalBucket> bucketMap;
+    // bucketMap gets lazily initialized from buckets in getBucketByKey()
+    private transient Map<String, InternalBucket> bucketMap;
 
-    public InternalFilters(String name, List<InternalBucket> buckets, boolean keyed, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
+    public InternalFilters(String name, List<InternalBucket> buckets, boolean keyed, List<PipelineAggregator> pipelineAggregators,
+            Map<String, Object> metaData) {
         super(name, pipelineAggregators, metaData);
         this.buckets = buckets;
         this.keyed = keyed;
@@ -200,7 +223,8 @@ public InternalAggregation doReduce(List<InternalAggregation> aggregations, Redu
             }
         }
 
-        InternalFilters reduced = new InternalFilters(name, new ArrayList<InternalBucket>(bucketsList.size()), keyed, pipelineAggregators(), getMetaData());
+        InternalFilters reduced = new InternalFilters(name, new ArrayList<InternalBucket>(bucketsList.size()), keyed, pipelineAggregators(),
+                getMetaData());
         for (List<InternalBucket> sameRangeList : bucketsList) {
             reduced.buckets.add((sameRangeList.get(0)).reduce(sameRangeList, reduceContext));
         }
@@ -225,4 +249,16 @@ public XContentBuilder doXContentBody(XContentBuilder builder, Params params) th
         return builder;
     }
 
+    @Override
+    protected int doHashCode() {
+        return Objects.hash(buckets, keyed);
+    }
+
+    @Override
+    protected boolean doEquals(Object obj) {
+        InternalFilters that = (InternalFilters) obj;
+        return Objects.equals(buckets, that.buckets)
+                && Objects.equals(keyed, that.keyed);
+    }
+
 }

core/src/test/java/org/elasticsearch/search/aggregations/bucket/filters/InternalFiltersTests.java

@@ -0,0 +1,83 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.search.aggregations.bucket.filters;
+
+import org.elasticsearch.common.io.stream.Writeable.Reader;
+import org.elasticsearch.search.aggregations.InternalAggregations;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
+import org.elasticsearch.test.InternalAggregationTestCase;
+import org.junit.Before;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+public class InternalFiltersTests extends InternalAggregationTestCase<InternalFilters> {
+
+    private boolean keyed;
+    private final List<String> keys = new ArrayList<>();
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        keyed = randomBoolean();
+        int numKeys = randomIntBetween(1,10);
+        for (int i = 0; i < numKeys; i++) {
+            keys.add(randomAlphaOfLength(5));
+        }
+
+    }
+
+    @Override
+    protected InternalFilters createTestInstance(String name, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
+        final List<InternalFilters.InternalBucket> buckets = new ArrayList<>();
+        for (int i = 0; i < keys.size(); ++i) {
+            String key = keys.get(i);
+            int docCount = randomIntBetween(0, 1000);
+            buckets.add( new InternalFilters.InternalBucket(key, docCount, InternalAggregations.EMPTY, keyed));
+        }
+        return new InternalFilters(name, buckets, keyed, pipelineAggregators, metaData);
+    }
+
+    @Override
+    protected void assertReduced(InternalFilters reduced, List<InternalFilters> inputs) {
+        final Map<String, Long> expectedCounts = new TreeMap<>();
+        for (InternalFilters input : inputs) {
+            for (InternalFilters.InternalBucket bucket : input.getBuckets()) {
+                expectedCounts.compute(bucket.getKeyAsString(),
+                        (key, oldValue) -> (oldValue == null ? 0 : oldValue) + bucket.getDocCount());
+            }
+        }
+        final Map<String, Long> actualCounts = new TreeMap<>();
+        for (InternalFilters.InternalBucket bucket : reduced.getBuckets()) {
+            actualCounts.compute(bucket.getKeyAsString(),
+                    (key, oldValue) -> (oldValue == null ? 0 : oldValue) + bucket.getDocCount());
+        }
+        assertEquals(expectedCounts, actualCounts);
+    }
+
+    @Override
+    protected Reader<InternalFilters> instanceReader() {
+        return InternalFilters::new;
+    }
+
+}