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 * 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
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package org.elasticsearch.search.aggregations.metrics.cardinality;

import org.elasticsearch.common.io.stream.Writeable.Reader;
import org.elasticsearch.common.lease.Releasables;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.util.MockBigArrays;
import org.elasticsearch.indices.breaker.NoneCircuitBreakerService;
import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
import org.elasticsearch.test.InternalAggregationTestCase;
import org.junit.After;
import org.junit.Before;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

public class InternalCardinalityTests extends InternalAggregationTestCase<InternalCardinality> {
    private static List<HyperLogLogPlusPlus> algos;
    private static int p;

    @Before
    public void setup() {
        algos = new ArrayList<>();
        p = randomIntBetween(HyperLogLogPlusPlus.MIN_PRECISION, HyperLogLogPlusPlus.MAX_PRECISION);
    }

    @Override
    protected InternalCardinality createTestInstance(String name,
            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
        HyperLogLogPlusPlus hllpp = new HyperLogLogPlusPlus(p,
                new MockBigArrays(Settings.EMPTY, new NoneCircuitBreakerService()), 1);
        algos.add(hllpp);
        for (int i = 0; i < 100; i++) {
            hllpp.collect(0, randomIntBetween(1, 100));
        }
        return new InternalCardinality(name, hllpp, pipelineAggregators, metaData);
    }

    @Override
    protected Reader<InternalCardinality> instanceReader() {
        return InternalCardinality::new;
    }

    @Override
    protected void assertReduced(InternalCardinality reduced, List<InternalCardinality> inputs) {
        HyperLogLogPlusPlus[] algos = inputs.stream().map(InternalCardinality::getState)
                .toArray(size -> new HyperLogLogPlusPlus[size]);
        if (algos.length > 0) {
            HyperLogLogPlusPlus result = algos[0];
            for (int i = 1; i < algos.length; i++) {
                result.merge(0, algos[i], 0);
            }
            assertEquals(result.cardinality(0), reduced.value(), 0);
        }
    }

    @After
    public void cleanup() {
        Releasables.close(algos);
        algos.clear();
        algos = null;
    }
}