[TEST] Added unittests for InternalGeoCentroid

Relates to #22278

core/src/main/java/org/elasticsearch/search/aggregations/metrics/geocentroid/InternalGeoCentroid.java

@@ -30,6 +30,7 @@
 import java.io.IOException;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 /**
  * Serialization and merge logic for {@link GeoCentroidAggregator}.
@@ -154,4 +155,24 @@ public XContentBuilder doXContentBody(XContentBuilder builder, Params params) th
         }
         return builder;
     }
+
+    @Override
+    public boolean doEquals(Object o) {
+        InternalGeoCentroid that = (InternalGeoCentroid) o;
+        return count == that.count &&
+                Objects.equals(centroid, that.centroid);
+    }
+
+    @Override
+    protected int doHashCode() {
+        return Objects.hash(centroid, count);
+    }
+
+    @Override
+    public String toString() {
+        return "InternalGeoCentroid{" +
+                "centroid=" + centroid +
+                ", count=" + count +
+                '}';
+    }
 }

core/src/test/java/org/elasticsearch/search/aggregations/metrics/geocentroid/InternalGeoCentroidTests.java

@@ -0,0 +1,66 @@
+/*
+ * 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.metrics.geocentroid;
+
+import org.apache.lucene.geo.GeoEncodingUtils;
+import org.elasticsearch.common.geo.GeoPoint;
+import org.elasticsearch.common.io.stream.Writeable;
+import org.elasticsearch.search.aggregations.InternalAggregationTestCase;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
+import org.elasticsearch.test.geo.RandomGeoGenerator;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+public class InternalGeoCentroidTests extends InternalAggregationTestCase<InternalGeoCentroid> {
+
+    @Override
+    protected InternalGeoCentroid createTestInstance(String name, List<PipelineAggregator> pipelineAggregators,
+                                                     Map<String, Object> metaData) {
+        GeoPoint centroid = RandomGeoGenerator.randomPoint(random());
+
+        // Re-encode lat/longs to avoid rounding issue when testing InternalGeoCentroid#hashCode() and
+        // InternalGeoCentroid#equals()
+        int encodedLon = GeoEncodingUtils.encodeLongitude(centroid.lon());
+        centroid.resetLon(GeoEncodingUtils.decodeLongitude(encodedLon));
+        int encodedLat = GeoEncodingUtils.encodeLatitude(centroid.lat());
+        centroid.resetLat(GeoEncodingUtils.decodeLatitude(encodedLat));
+
+        return new InternalGeoCentroid("_name", centroid, 1, Collections.emptyList(), Collections.emptyMap());
+    }
+
+    @Override
+    protected Writeable.Reader<InternalGeoCentroid> instanceReader() {
+        return InternalGeoCentroid::new;
+    }
+
+    @Override
+    protected void assertReduced(InternalGeoCentroid reduced, List<InternalGeoCentroid> inputs) {
+        GeoPoint expected = new GeoPoint(0, 0);
+        int i = 0;
+        for (InternalGeoCentroid input : inputs) {
+            expected.reset(expected.lat() + (input.centroid().lat() - expected.lat()) / (i+1),
+                    expected.lon() + (input.centroid().lon() - expected.lon()) / (i+1));
+            i++;
+        }
+        assertEquals(expected.getLat(), reduced.centroid().getLat(), 1E-5D);
+        assertEquals(expected.getLon(), reduced.centroid().getLon(), 1E-5D);
+    }
+}