Tests: Add unit test for InternalDateHistogram (#23402)

Relates to #22278

core/src/main/java/org/elasticsearch/search/aggregations/bucket/histogram/InternalDateHistogram.java

@@ -41,6 +41,7 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.ListIterator;
 import java.util.Map;
+import java.util.Objects;
 
 /**
  * Implementation of {@link Histogram}.
@@ -76,6 +77,24 @@ public final class InternalDateHistogram extends InternalMultiBucketAggregation<
             aggregations = InternalAggregations.readAggregations(in);
         }
 
+        @Override
+        public boolean equals(Object obj) {
+            if (obj == null || obj.getClass() != InternalDateHistogram.Bucket.class) {
+                return false;
+            }
+            InternalDateHistogram.Bucket that = (InternalDateHistogram.Bucket) obj;
+            // No need to take the keyed and format parameters into account,
+            // they are already stored and tested on the InternalDateHistogram object
+            return key == that.key
+                    && docCount == that.docCount
+                    && Objects.equals(aggregations, that.aggregations);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(getClass(), key, docCount, aggregations);
+        }
+
         @Override
         public void writeTo(StreamOutput out) throws IOException {
             out.writeLong(key);
@@ -169,6 +188,21 @@ public final class InternalDateHistogram extends InternalMultiBucketAggregation<
             out.writeOptionalWriteable(bounds);
         }
 
+        @Override
+        public boolean equals(Object obj) {
+            if (obj == null || getClass() != obj.getClass()) {
+                return false;
+            }
+            EmptyBucketInfo that = (EmptyBucketInfo) obj;
+            return Objects.equals(rounding, that.rounding)
+                    && Objects.equals(bounds, that.bounds)
+                    && Objects.equals(subAggregations, that.subAggregations);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(getClass(), rounding, bounds, subAggregations);
+        }
     }
 
     private final List<Bucket> buckets;
@@ -446,4 +480,21 @@ public final class InternalDateHistogram extends InternalMultiBucketAggregation<
     public Bucket createBucket(Number key, long docCount, InternalAggregations aggregations) {
         return new Bucket(key.longValue(), docCount, keyed, format, aggregations);
     }
+
+    @Override
+    protected boolean doEquals(Object obj) {
+        InternalDateHistogram that = (InternalDateHistogram) obj;
+        return Objects.equals(buckets, that.buckets)
+                && Objects.equals(order, that.order)
+                && Objects.equals(format, that.format)
+                && Objects.equals(keyed, that.keyed)
+                && Objects.equals(minDocCount, that.minDocCount)
+                && Objects.equals(offset, that.offset)
+                && Objects.equals(emptyBucketInfo, that.emptyBucketInfo);
+    }
+
+    @Override
+    protected int doHashCode() {
+        return Objects.hash(buckets, order, format, keyed, minDocCount, offset, emptyBucketInfo);
+    }
 }

core/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/InternalDateHistogramTests.java

@@ -0,0 +1,85 @@
+/*
+ * 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.histogram;
+
+import org.apache.lucene.util.TestUtil;
+import org.elasticsearch.common.io.stream.Writeable;
+import org.elasticsearch.common.unit.TimeValue;
+import org.elasticsearch.search.DocValueFormat;
+import org.elasticsearch.search.aggregations.InternalAggregationTestCase;
+import org.elasticsearch.search.aggregations.InternalAggregations;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
+import org.joda.time.DateTime;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+import static org.elasticsearch.common.unit.TimeValue.timeValueHours;
+import static org.elasticsearch.common.unit.TimeValue.timeValueMinutes;
+import static org.elasticsearch.common.unit.TimeValue.timeValueSeconds;
+
+public class InternalDateHistogramTests extends InternalAggregationTestCase<InternalDateHistogram> {
+
+    @Override
+    protected InternalDateHistogram createTestInstance(String name, List<PipelineAggregator> pipelineAggregators,
+                                                       Map<String, Object> metaData) {
+
+        boolean keyed = randomBoolean();
+        DocValueFormat format = DocValueFormat.RAW;
+        int nbBuckets = randomInt(10);
+        List<InternalDateHistogram.Bucket> buckets = new ArrayList<>(nbBuckets);
+        long startingDate = System.currentTimeMillis();
+
+        long interval = randomIntBetween(1, 3);
+        long intervalMillis = randomFrom(timeValueSeconds(interval), timeValueMinutes(interval), timeValueHours(interval)).getMillis();
+
+        for (int i = 0; i < nbBuckets; i++) {
+            long key = startingDate + (intervalMillis * i);
+            buckets.add(i, new InternalDateHistogram.Bucket(key, randomIntBetween(1, 100), keyed, format, InternalAggregations.EMPTY));
+        }
+
+        InternalOrder order = (InternalOrder) randomFrom(InternalHistogram.Order.KEY_ASC, InternalHistogram.Order.KEY_DESC);
+        return new InternalDateHistogram(name, buckets, order, 1, 0L, null, format, keyed, pipelineAggregators, metaData);
+    }
+
+    @Override
+    protected void assertReduced(InternalDateHistogram reduced, List<InternalDateHistogram> inputs) {
+        Map<Long, Long> expectedCounts = new TreeMap<>();
+        for (Histogram histogram : inputs) {
+            for (Histogram.Bucket bucket : histogram.getBuckets()) {
+                expectedCounts.compute(((DateTime) bucket.getKey()).getMillis(),
+                        (key, oldValue) -> (oldValue == null ? 0 : oldValue) + bucket.getDocCount());
+            }
+        }
+        Map<Long, Long> actualCounts = new TreeMap<>();
+        for (Histogram.Bucket bucket : reduced.getBuckets()) {
+            actualCounts.compute(((DateTime) bucket.getKey()).getMillis(),
+                    (key, oldValue) -> (oldValue == null ? 0 : oldValue) + bucket.getDocCount());
+        }
+        assertEquals(expectedCounts, actualCounts);
+    }
+
+    @Override
+    protected Writeable.Reader<InternalDateHistogram> instanceReader() {
+        return InternalDateHistogram::new;
+    }
+}