text: /**
   *    Copyright (C) 2012-2014 MongoDB Inc.
   *
   *    This program is free software: you can redistribute it and/or  modify
   *    it under the terms of the GNU Affero General Public License, version 3,
   *    as published by the Free Software Foundation.
   *
   *    This program is distributed in the hope that it will be useful,
   *    but WITHOUT ANY WARRANTY; without even the implied warranty of
   *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *    GNU Affero General Public License for more details.
   *
   *    You should have received a copy of the GNU Affero General Public License
   *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
   *
   *    As a special exception, the copyright holders give permission to link the
   *    code of portions of this program with the OpenSSL library under certain
   *    conditions as described in each individual source file and distribute
   *    linked combinations including the program with the OpenSSL library. You
   *    must comply with the GNU Affero General Public License in all respects
   *    for all of the code used other than as permitted herein. If you modify
   *    file(s) with this exception, you may extend this exception to your
   *    version of the file(s), but you are not obligated to do so. If you do not
   *    wish to do so, delete this exception statement from your version. If you
   *    delete this exception statement from all source files in the program,
   *    then also delete it in the license file.
   */
  
  #include "mongo/platform/basic.h"
  
  #include "mongo/bson/bsonmisc.h"
  #include "mongo/bson/bsonobj.h"
  #include "mongo/bson/bsonobjbuilder.h"
  #include "mongo/db/pipeline/document_source.h"
  #include "mongo/unittest/unittest.h"
  
  namespace mongo {
  
  namespace {
  
  TEST(TruncateSort, SortTruncatesNormalField) {
      SimpleBSONObjComparator bsonComparator{};
      BSONObj sortKey = BSON("a" << 1 << "b" << 1 << "c" << 1);
      auto truncated =
          DocumentSource::truncateSortSet(bsonComparator.makeBSONObjSet({sortKey}), {"b"});
      ASSERT_EQUALS(truncated.size(), 1U);
      ASSERT_EQUALS(truncated.count(BSON("a" << 1)), 1U);
  }
  
  TEST(DocumentSourceTruncateSort, SortTruncatesOnSubfield) {
      SimpleBSONObjComparator bsonComparator{};
      BSONObj sortKey = BSON("a" << 1 << "b.c" << 1 << "d" << 1);
      auto truncated =
          DocumentSource::truncateSortSet(bsonComparator.makeBSONObjSet({sortKey}), {"b"});
      ASSERT_EQUALS(truncated.size(), 1U);
      ASSERT_EQUALS(truncated.count(BSON("a" << 1)), 1U);
  }
  
  TEST(DocumentSourceTruncateSort, SortDoesNotTruncateOnParent) {
      SimpleBSONObjComparator bsonComparator{};
      BSONObj sortKey = BSON("a" << 1 << "b" << 1 << "d" << 1);
      auto truncated =
          DocumentSource::truncateSortSet(bsonComparator.makeBSONObjSet({sortKey}), {"b.c"});
      ASSERT_EQUALS(truncated.size(), 1U);
      ASSERT_EQUALS(truncated.count(BSON("a" << 1 << "b" << 1 << "d" << 1)), 1U);
  }
  
  TEST(DocumentSourceTruncateSort, TruncateSortDedupsSortCorrectly) {
      SimpleBSONObjComparator bsonComparator{};
      BSONObj sortKeyOne = BSON("a" << 1 << "b" << 1);
      BSONObj sortKeyTwo = BSON("a" << 1);
      auto truncated = DocumentSource::truncateSortSet(
          bsonComparator.makeBSONObjSet({sortKeyOne, sortKeyTwo}), {"b"});
      ASSERT_EQUALS(truncated.size(), 1U);
      ASSERT_EQUALS(truncated.count(BSON("a" << 1)), 1U);
  }
  
  }  // namespace
  }  // namespace mongo
  