text: /*
    Tencent is pleased to support the open source community by making
    Plato available.
    Copyright (C) 2019 THL A29 Limited, a Tencent company.
    All rights reserved.
  
    Licensed under the BSD 3-Clause License (the "License"); you may
    not use this file except in compliance with the License. You may
    obtain a copy of the License at
  
    https://opensource.org/licenses/BSD-3-Clause
  
    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.
  
    See the AUTHORS file for names of contributors.
  */
  
  #include <cmath>
  #include <cfloat>
  #include "gtest/gtest.h"
  #include "plato/util/hyperloglog.hpp"
  #include "glog/logging.h"
  
  TEST(HyperLogLog, Add) {
    plato::hyperloglog_t<6> hll;
    hll.init();
    hll.clear();
  
    for (int i = 0; i < 1000; ++i) {
      hll.add(&i, sizeof(i));
    }
  
    double cardinality = hll.estimate();
    ASSERT_GE(0.25, fabs(cardinality - 1000) / 1000);
  }
  
  TEST(HyperLogLog, Merge) {
    plato::hyperloglog_t<12> hll1;
    hll1.init();
    hll1.clear();
    plato::hyperloglog_t<12> hll2;
    hll2.init();
    hll2.clear();
  ;
    for (int i = 0; i < 1000; ++i) {
      hll1.add(&i, sizeof(i));
      hll2.add(&i, sizeof(i));
    }
    double cardinality1 = hll1.estimate();
    hll1.merge(hll2);
    double cardinality2 = hll1.estimate();
    ASSERT_GE(DBL_EPSILON, fabs(cardinality1 - cardinality2));
  
    hll2.clear();
    int x = 1000;
    hll2.add(&x, sizeof(x));
    hll1.merge(hll2);
    cardinality2 = hll1.estimate();
    ASSERT_GE(cardinality2, cardinality1);
  }
  