////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2017 ArangoDB GmbH, Cologne, Germany
///
/// Licensed 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.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Andrey Abramov
/// @author Vasiliy Nabatchikov
////////////////////////////////////////////////////////////////////////////////

#include "catch.hpp"
#include "common.h"

#include "StorageEngineMock.h"

#if USE_ENTERPRISE
  #include "Enterprise/Ldap/LdapFeature.h"
#endif

#include "V8/v8-globals.h"
#include "VocBase/LogicalCollection.h"
#include "VocBase/LogicalView.h"
#include "Transaction/StandaloneContext.h"
#include "Utils/OperationOptions.h"
#include "Utils/SingleCollectionTransaction.h"
#include "Aql/AqlFunctionFeature.h"
#include "Aql/OptimizerRulesFeature.h"
#include "GeneralServer/AuthenticationFeature.h"
#include "IResearch/IResearchCommon.h"
#include "IResearch/IResearchFeature.h"
#include "IResearch/IResearchFilterFactory.h"
#include "IResearch/IResearchView.h"
#include "IResearch/IResearchAnalyzerFeature.h"
#include "Logger/Logger.h"
#include "Logger/LogTopic.h"
#include "StorageEngine/EngineSelectorFeature.h"
#include "RestServer/DatabasePathFeature.h"
#include "RestServer/ViewTypesFeature.h"
#include "RestServer/AqlFeature.h"
#include "RestServer/DatabaseFeature.h"
#include "RestServer/QueryRegistryFeature.h"
#include "RestServer/SystemDatabaseFeature.h"
#include "RestServer/TraverserEngineRegistryFeature.h"
#include "Sharding/ShardingFeature.h"
#include "Basics/VelocyPackHelper.h"
#include "Aql/Ast.h"
#include "Aql/Query.h"
#include "3rdParty/iresearch/tests/tests_config.hpp"

#include "IResearch/VelocyPackHelper.h"
#include "analysis/analyzers.hpp"
#include "analysis/token_attributes.hpp"
#include "utils/utf8_path.hpp"

#include <velocypack/Iterator.h>

extern const char* ARGV0; // defined in main.cpp

NS_LOCAL

// -----------------------------------------------------------------------------
// --SECTION--                                                 setup / tear-down
// -----------------------------------------------------------------------------

struct IResearchQueryNullTermSetup {
  StorageEngineMock engine;
  arangodb::application_features::ApplicationServer server;
  std::unique_ptr<TRI_vocbase_t> system;
  std::vector<std::pair<arangodb::application_features::ApplicationFeature*, bool>> features;

  IResearchQueryNullTermSetup(): engine(server), server(nullptr, nullptr) {
    arangodb::EngineSelectorFeature::ENGINE = &engine;

    arangodb::tests::init(true);

    // suppress INFO {authentication} Authentication is turned on (system only), authentication for unix sockets is turned on
    arangodb::LogTopic::setLogLevel(arangodb::Logger::AUTHENTICATION.name(), arangodb::LogLevel::WARN);

    // suppress log messages since tests check error conditions
    arangodb::LogTopic::setLogLevel(arangodb::Logger::FIXME.name(), arangodb::LogLevel::ERR); // suppress WARNING DefaultCustomTypeHandler called
    arangodb::LogTopic::setLogLevel(arangodb::iresearch::TOPIC.name(), arangodb::LogLevel::FATAL);
    irs::logger::output_le(iresearch::logger::IRL_FATAL, stderr);

    // setup required application features
    features.emplace_back(new arangodb::ViewTypesFeature(server), true);
    features.emplace_back(new arangodb::AuthenticationFeature(server), true);
    features.emplace_back(new arangodb::DatabasePathFeature(server), false);
    features.emplace_back(new arangodb::DatabaseFeature(server), false);
    features.emplace_back(new arangodb::ShardingFeature(server), false);
    features.emplace_back(new arangodb::QueryRegistryFeature(server), false); // must be first
    arangodb::application_features::ApplicationServer::server->addFeature(features.back().first); // need QueryRegistryFeature feature to be added now in order to create the system database
    system = irs::memory::make_unique<TRI_vocbase_t>(TRI_vocbase_type_e::TRI_VOCBASE_TYPE_NORMAL, 0, TRI_VOC_SYSTEM_DATABASE);
    features.emplace_back(new arangodb::SystemDatabaseFeature(server, system.get()), false); // required for IResearchAnalyzerFeature
    features.emplace_back(new arangodb::TraverserEngineRegistryFeature(server), false); // must be before AqlFeature
    features.emplace_back(new arangodb::AqlFeature(server), true);
    features.emplace_back(new arangodb::aql::OptimizerRulesFeature(server), true);
    features.emplace_back(new arangodb::aql::AqlFunctionFeature(server), true); // required for IResearchAnalyzerFeature
    features.emplace_back(new arangodb::iresearch::IResearchAnalyzerFeature(server), true);
    features.emplace_back(new arangodb::iresearch::IResearchFeature(server), true);

    #if USE_ENTERPRISE
      features.emplace_back(new arangodb::LdapFeature(server), false); // required for AuthenticationFeature with USE_ENTERPRISE
    #endif

    for (auto& f : features) {
      arangodb::application_features::ApplicationServer::server->addFeature(f.first);
    }

    for (auto& f : features) {
      f.first->prepare();
    }

    for (auto& f : features) {
      if (f.second) {
        f.first->start();
      }
    }

    auto* analyzers = arangodb::application_features::ApplicationServer::lookupFeature<
      arangodb::iresearch::IResearchAnalyzerFeature
    >();

    analyzers->emplace("test_analyzer", "TestAnalyzer", "abc"); // cache analyzer
    analyzers->emplace("test_csv_analyzer", "TestDelimAnalyzer", ","); // cache analyzer

    auto* dbPathFeature = arangodb::application_features::ApplicationServer::getFeature<arangodb::DatabasePathFeature>("DatabasePath");
    arangodb::tests::setDatabasePath(*dbPathFeature); // ensure test data is stored in a unique directory
  }

  ~IResearchQueryNullTermSetup() {
    system.reset(); // destroy before reseting the 'ENGINE'
    arangodb::AqlFeature(server).stop(); // unset singleton instance
    arangodb::LogTopic::setLogLevel(arangodb::iresearch::TOPIC.name(), arangodb::LogLevel::DEFAULT);
    arangodb::LogTopic::setLogLevel(arangodb::Logger::FIXME.name(), arangodb::LogLevel::DEFAULT);
    arangodb::application_features::ApplicationServer::server = nullptr;
    arangodb::EngineSelectorFeature::ENGINE = nullptr;

    // destroy application features
    for (auto& f : features) {
      if (f.second) {
        f.first->stop();
      }
    }

    for (auto& f : features) {
      f.first->unprepare();
    }

    arangodb::LogTopic::setLogLevel(arangodb::Logger::AUTHENTICATION.name(), arangodb::LogLevel::DEFAULT);
  }
}; // IResearchQuerySetup

NS_END

// -----------------------------------------------------------------------------
// --SECTION--                                                        test suite
// -----------------------------------------------------------------------------

////////////////////////////////////////////////////////////////////////////////
/// @brief setup
////////////////////////////////////////////////////////////////////////////////

TEST_CASE("IResearchQueryTestNullTerm", "[iresearch][iresearch-query]") {
  IResearchQueryNullTermSetup s;
  UNUSED(s);

  TRI_vocbase_t vocbase(TRI_vocbase_type_e::TRI_VOCBASE_TYPE_NORMAL, 1, "testVocbase");
  arangodb::LogicalView* view{};
  std::vector<arangodb::velocypack::Builder> insertedDocs;

  // create collection0
  {
    auto createJson = arangodb::velocypack::Parser::fromJson("{ \"name\": \"testCollection0\" }");
    auto collection = vocbase.createCollection(createJson->slice());
    REQUIRE((nullptr != collection));

    std::vector<std::shared_ptr<arangodb::velocypack::Builder>> docs {
      arangodb::velocypack::Parser::fromJson("{ \"seq\": -7 }"),
      arangodb::velocypack::Parser::fromJson("{ \"seq\": -6, \"value\": null}"),
      arangodb::velocypack::Parser::fromJson("{ \"seq\": -5, \"value\": null}"),
      arangodb::velocypack::Parser::fromJson("{ \"seq\": -4 }"),
      arangodb::velocypack::Parser::fromJson("{ \"seq\": -3, \"value\": null}"),
      arangodb::velocypack::Parser::fromJson("{ \"seq\": -2, \"value\": null}"),
      arangodb::velocypack::Parser::fromJson("{ \"seq\": -1 }"),
      arangodb::velocypack::Parser::fromJson("{ \"seq\": 0, \"value\": null }"),
      arangodb::velocypack::Parser::fromJson("{ \"seq\": 1 }")
    };

    arangodb::OperationOptions options;
    options.returnNew = true;
    arangodb::SingleCollectionTransaction trx(
      arangodb::transaction::StandaloneContext::Create(vocbase),
      *collection,
      arangodb::AccessMode::Type::WRITE
    );
    CHECK((trx.begin().ok()));

    for (auto& entry: docs) {
      auto res = trx.insert(collection->name(), entry->slice(), options);
      CHECK((res.ok()));
      insertedDocs.emplace_back(res.slice().get("new"));
    }

    CHECK((trx.commit().ok()));
  }

  // create collection1
  {
    auto createJson = arangodb::velocypack::Parser::fromJson("{ \"name\": \"testCollection1\" }");
    auto collection = vocbase.createCollection(createJson->slice());
    REQUIRE((nullptr != collection));

    std::vector<std::shared_ptr<arangodb::velocypack::Builder>> docs {
      arangodb::velocypack::Parser::fromJson("{ \"seq\": 2, \"value\": null}"),
      arangodb::velocypack::Parser::fromJson("{ \"seq\": 3 }"),
      arangodb::velocypack::Parser::fromJson("{ \"seq\": 4 }"),
      arangodb::velocypack::Parser::fromJson("{ \"seq\": 5 }"),
      arangodb::velocypack::Parser::fromJson("{ \"seq\": 6, \"value\": null}"),
      arangodb::velocypack::Parser::fromJson("{ \"seq\": 7, \"value\": null}"),
      arangodb::velocypack::Parser::fromJson("{ \"seq\": 8 }")
    };

    arangodb::OperationOptions options;
    options.returnNew = true;
    arangodb::SingleCollectionTransaction trx(
      arangodb::transaction::StandaloneContext::Create(vocbase),
      *collection,
      arangodb::AccessMode::Type::WRITE
    );
    CHECK((trx.begin().ok()));

    for (auto& entry: docs) {
      auto res = trx.insert(collection->name(), entry->slice(), options);
      CHECK((res.ok()));
      insertedDocs.emplace_back(res.slice().get("new"));
    }

    CHECK((trx.commit().ok()));
  }

  // create view
  {
    auto createJson = arangodb::velocypack::Parser::fromJson("{ \"name\": \"testView\", \"type\": \"arangosearch\" }");
    auto logicalView = vocbase.createView(createJson->slice());
    REQUIRE((false == !logicalView));

    view = logicalView.get();
    REQUIRE(nullptr != view);
    auto* impl = dynamic_cast<arangodb::iresearch::IResearchView*>(view);
    REQUIRE((false == !impl));

    auto updateJson = arangodb::velocypack::Parser::fromJson(
      "{ \"links\": {"
        "\"testCollection0\": { \"includeAllFields\": true, \"trackListPositions\": true },"
        "\"testCollection1\": { \"includeAllFields\": true }"
      "}}"
    );
    CHECK((impl->properties(updateJson->slice(), true).ok()));
    std::set<TRI_voc_cid_t> cids;
    impl->visitCollections([&cids](TRI_voc_cid_t cid)->bool { cids.emplace(cid); return true; });
    CHECK((2 == cids.size()));
    CHECK(impl->commit().ok());
  }

  // -----------------------------------------------------------------------------
  // --SECTION--                                                                ==
  // -----------------------------------------------------------------------------

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value == 'null' RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value == 0 RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // d.value == null, unordered
  {
    std::map<size_t, arangodb::velocypack::Slice> expectedDocs;
    for (auto const& doc : insertedDocs) {
      arangodb::velocypack::Slice docSlice = doc.slice().resolveExternals();
      auto const valueSlice = docSlice.get("value");

      if (valueSlice.isNone() || !valueSlice.isNull()) {
        continue;
      }

      auto const keySlice = docSlice.get("seq");
      expectedDocs.emplace(keySlice.getNumber<ptrdiff_t>(), docSlice);
    }

    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value == null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(expectedDocs.size() == resultIt.size());

    for (auto const actualDoc : resultIt) {
      auto const resolved = actualDoc.resolveExternals();
      auto const keySlice = resolved.get("seq");
      auto const key = keySlice.getNumber<ptrdiff_t>();

      auto expectedDoc = expectedDocs.find(key);
      REQUIRE(expectedDoc != expectedDocs.end());
      CHECK(0 == arangodb::basics::VelocyPackHelper::compare(expectedDoc->second, resolved, true));
      expectedDocs.erase(expectedDoc);
    }
    CHECK(expectedDocs.empty());
  }

  // d.value == null, BM25(), TFIDF(), d.seq DESC
  {
    std::map<ptrdiff_t, arangodb::velocypack::Slice> expectedDocs;
    for (auto const& doc : insertedDocs) {
      arangodb::velocypack::Slice docSlice = doc.slice().resolveExternals();
      auto const valueSlice = docSlice.get("value");

      if (valueSlice.isNone() || !valueSlice.isNull()) {
        continue;
      }

      auto const keySlice = docSlice.get("seq");
      expectedDocs.emplace(keySlice.getNumber<ptrdiff_t>(), docSlice);
    }

    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value == null SORT BM25(d), TFIDF(d), d.seq DESC RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(expectedDocs.size() == resultIt.size());

    auto expectedDoc = expectedDocs.rbegin();
    for (auto const actualDoc : resultIt) {
      auto const resolved = actualDoc.resolveExternals();
      CHECK(0 == arangodb::basics::VelocyPackHelper::compare(expectedDoc->second, resolved, true));
      ++expectedDoc;
    }
    CHECK(expectedDoc == expectedDocs.rend());
  }

  // -----------------------------------------------------------------------------
  // --SECTION--                                                                !=
  // -----------------------------------------------------------------------------

  // invalid type
  {
    std::map<ptrdiff_t, arangodb::velocypack::Slice> expectedDocs;
    for (auto const& doc : insertedDocs) {
      arangodb::velocypack::Slice docSlice = doc.slice().resolveExternals();
      auto const keySlice = docSlice.get("seq");
      auto const fieldSlice = docSlice.get("value");

      if (!fieldSlice.isNone() && "null"  == arangodb::iresearch::getStringRef(fieldSlice)) {
        continue;
      }

      expectedDocs.emplace(keySlice.getNumber<ptrdiff_t>(), docSlice);
    }

    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value != 'null' RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(expectedDocs.size() == resultIt.size());

    for (auto const actualDoc : resultIt) {
      auto const resolved = actualDoc.resolveExternals();
      auto const keySlice = resolved.get("seq");
      auto const key = keySlice.getNumber<ptrdiff_t>();

      auto expectedDoc = expectedDocs.find(key);
      REQUIRE(expectedDoc != expectedDocs.end());
      CHECK(0 == arangodb::basics::VelocyPackHelper::compare(expectedDoc->second, resolved, true));
      expectedDocs.erase(expectedDoc);
    }
    CHECK(expectedDocs.empty());
  }

  // invalid type
  {
    std::map<ptrdiff_t, arangodb::velocypack::Slice> expectedDocs;
    for (auto const& doc : insertedDocs) {
      arangodb::velocypack::Slice docSlice = doc.slice().resolveExternals();
      auto const keySlice = docSlice.get("seq");
      auto const fieldSlice = docSlice.get("value");

      if (!fieldSlice.isNone() && (fieldSlice.isNumber() && 0. == fieldSlice.getNumber<double>())) {
        continue;
      }

      expectedDocs.emplace(keySlice.getNumber<ptrdiff_t>(), docSlice);
    }

    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value != 0 RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(expectedDocs.size() == resultIt.size());

    for (auto const actualDoc : resultIt) {
      auto const resolved = actualDoc.resolveExternals();
      auto const keySlice = resolved.get("seq");
      auto const key = keySlice.getNumber<ptrdiff_t>();

      auto expectedDoc = expectedDocs.find(key);
      REQUIRE(expectedDoc != expectedDocs.end());
      CHECK(0 == arangodb::basics::VelocyPackHelper::compare(expectedDoc->second, resolved, true));
      expectedDocs.erase(expectedDoc);
    }
    CHECK(expectedDocs.empty());
  }

  // d.value != null, unordered
  {
    std::map<size_t, arangodb::velocypack::Slice> expectedDocs;
    for (auto const& doc : insertedDocs) {
      arangodb::velocypack::Slice docSlice = doc.slice().resolveExternals();
      auto const valueSlice = docSlice.get("value");

      if (!valueSlice.isNone() && valueSlice.isNull()) {
        continue;
      }

      auto const keySlice = docSlice.get("seq");
      expectedDocs.emplace(keySlice.getNumber<ptrdiff_t>(), docSlice);
    }

    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value != null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(expectedDocs.size() == resultIt.size());

    for (auto const actualDoc : resultIt) {
      auto const resolved = actualDoc.resolveExternals();
      auto const keySlice = resolved.get("seq");
      auto const key = keySlice.getNumber<ptrdiff_t>();

      auto expectedDoc = expectedDocs.find(key);
      REQUIRE(expectedDoc != expectedDocs.end());
      CHECK(0 == arangodb::basics::VelocyPackHelper::compare(expectedDoc->second, resolved, true));
      expectedDocs.erase(expectedDoc);
    }
    CHECK(expectedDocs.empty());
  }

  // d.value != null, BM25(), TFIDF(), d.seq DESC
  {
    std::map<ptrdiff_t, arangodb::velocypack::Slice> expectedDocs;
    for (auto const& doc : insertedDocs) {
      arangodb::velocypack::Slice docSlice = doc.slice().resolveExternals();
      auto const valueSlice = docSlice.get("value");

      if (!valueSlice.isNone() && valueSlice.isNull()) {
        continue;
      }

      auto const keySlice = docSlice.get("seq");
      expectedDocs.emplace(keySlice.getNumber<ptrdiff_t>(), docSlice);
    }

    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value != null SORT BM25(d), TFIDF(d), d.seq DESC RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(expectedDocs.size() == resultIt.size());

    auto expectedDoc = expectedDocs.rbegin();
    for (auto const actualDoc : resultIt) {
      auto const resolved = actualDoc.resolveExternals();
      CHECK(0 == arangodb::basics::VelocyPackHelper::compare(expectedDoc->second, resolved, true));
      ++expectedDoc;
    }
    CHECK(expectedDoc == expectedDocs.rend());
  }

  // -----------------------------------------------------------------------------
  // --SECTION--                                                                 <
  // -----------------------------------------------------------------------------

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value < 'null' RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value < false RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value < 0 RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // d.value < null
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value < null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // -----------------------------------------------------------------------------
  // --SECTION--                                                                <=
  // -----------------------------------------------------------------------------

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value <= 'null' RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value <= false RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value <= 0 RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // d.value <= null, unordered
  {
    std::map<size_t, arangodb::velocypack::Slice> expectedDocs;
    for (auto const& doc : insertedDocs) {
      arangodb::velocypack::Slice docSlice = doc.slice().resolveExternals();
      auto const valueSlice = docSlice.get("value");
      if (valueSlice.isNone() || !valueSlice.isNull()) {
        continue;
      }
      auto const keySlice = docSlice.get("seq");
      expectedDocs.emplace(keySlice.getNumber<ptrdiff_t>(), docSlice);
    }

    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value <= null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(expectedDocs.size() == resultIt.size());

    for (auto const actualDoc : resultIt) {
      auto const resolved = actualDoc.resolveExternals();
      auto const keySlice = resolved.get("seq");
      auto const key = keySlice.getNumber<ptrdiff_t>();

      auto expectedDoc = expectedDocs.find(key);
      REQUIRE(expectedDoc != expectedDocs.end());
      CHECK(0 == arangodb::basics::VelocyPackHelper::compare(expectedDoc->second, resolved, true));
      expectedDocs.erase(expectedDoc);
    }
    CHECK(expectedDocs.empty());
  }

  // d.value <= null, BM25(), TFIDF(), d.seq DESC
  {
    std::map<ptrdiff_t, arangodb::velocypack::Slice> expectedDocs;
    for (auto const& doc : insertedDocs) {
      arangodb::velocypack::Slice docSlice = doc.slice().resolveExternals();
      auto const valueSlice = docSlice.get("value");
      if (valueSlice.isNone() || !valueSlice.isNull()) {
        continue;
      }
      auto const keySlice = docSlice.get("seq");
      expectedDocs.emplace(keySlice.getNumber<ptrdiff_t>(), docSlice);
    }

    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value <= null SORT BM25(d), TFIDF(d), d.seq DESC RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(expectedDocs.size() == resultIt.size());

    auto expectedDoc = expectedDocs.rbegin();
    for (auto const actualDoc : resultIt) {
      auto const resolved = actualDoc.resolveExternals();
      CHECK(0 == arangodb::basics::VelocyPackHelper::compare(expectedDoc->second, resolved, true));
      ++expectedDoc;
    }
    CHECK(expectedDoc == expectedDocs.rend());
  }

  // -----------------------------------------------------------------------------
  // --SECTION--                                                                 >
  // -----------------------------------------------------------------------------

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value > 'null' RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value > false RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value > 0 RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // d.value > null
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value > null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // -----------------------------------------------------------------------------
  // --SECTION--                                                                >=
  // -----------------------------------------------------------------------------

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value >= 'null' RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value >= 0 RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value >= false RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // d.value >= null, unordered
  {
    std::map<size_t, arangodb::velocypack::Slice> expectedDocs;
    for (auto const& doc : insertedDocs) {
      arangodb::velocypack::Slice docSlice = doc.slice().resolveExternals();
      auto const valueSlice = docSlice.get("value");
      if (valueSlice.isNone() || !valueSlice.isNull()) {
        continue;
      }
      auto const keySlice = docSlice.get("seq");
      expectedDocs.emplace(keySlice.getNumber<ptrdiff_t>(), docSlice);
    }

    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value >= null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(expectedDocs.size() == resultIt.size());

    for (auto const actualDoc : resultIt) {
      auto const resolved = actualDoc.resolveExternals();
      auto const keySlice = resolved.get("seq");
      auto const key = keySlice.getNumber<ptrdiff_t>();

      auto expectedDoc = expectedDocs.find(key);
      REQUIRE(expectedDoc != expectedDocs.end());
      CHECK(0 == arangodb::basics::VelocyPackHelper::compare(expectedDoc->second, resolved, true));
      expectedDocs.erase(expectedDoc);
    }
    CHECK(expectedDocs.empty());
  }

  // d.value >= null, BM25(), TFIDF(), d.seq DESC
  {
    std::map<ptrdiff_t, arangodb::velocypack::Slice> expectedDocs;
    for (auto const& doc : insertedDocs) {
      arangodb::velocypack::Slice docSlice = doc.slice().resolveExternals();
      auto const valueSlice = docSlice.get("value");
      if (valueSlice.isNone() || !valueSlice.isNull()) {
        continue;
      }
      auto const keySlice = docSlice.get("seq");
      expectedDocs.emplace(keySlice.getNumber<ptrdiff_t>(), docSlice);
    }

    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value >= null SORT BM25(d), TFIDF(d), d.seq DESC RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(expectedDocs.size() == resultIt.size());

    auto expectedDoc = expectedDocs.rbegin();
    for (auto const actualDoc : resultIt) {
      auto const resolved = actualDoc.resolveExternals();
      CHECK(0 == arangodb::basics::VelocyPackHelper::compare(expectedDoc->second, resolved, true));
      ++expectedDoc;
    }
    CHECK(expectedDoc == expectedDocs.rend());
  }

  // -----------------------------------------------------------------------------
  // --SECTION--                                                       Range(>, <)
  // -----------------------------------------------------------------------------

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value > 'null' and d.value < null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value > 0 and d.value < null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value > false and d.value < null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // empty range
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value > null and d.value < null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // -----------------------------------------------------------------------------
  // --SECTION--                                                      Range(>=, <)
  // -----------------------------------------------------------------------------

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value >= 'null' and d.value < null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value >= 0 and d.value < null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value >= false and d.value < null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // empty range
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value >= null and d.value < null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // -----------------------------------------------------------------------------
  // --SECTION--                                                      Range(>, <=)
  // -----------------------------------------------------------------------------

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value > 'null' and d.value <= null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value > 0 and d.value <= null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value > false and d.value <= null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // empty range
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value > null and d.value <= null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // -----------------------------------------------------------------------------
  // --SECTION--                                                     Range(>=, <=)
  // -----------------------------------------------------------------------------

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value >= 'null' and d.value <= null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value >= 0 and d.value <= null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // invalid type
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value >= false and d.value <= null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());

    for (auto const actualDoc : resultIt) {
      UNUSED(actualDoc);
      CHECK(false);
    }
  }

  // d.value >= null and d.value <= null, unordered
  {
    std::map<size_t, arangodb::velocypack::Slice> expectedDocs;
    for (auto const& doc : insertedDocs) {
      arangodb::velocypack::Slice docSlice = doc.slice().resolveExternals();
      auto const valueSlice = docSlice.get("value");
      if (valueSlice.isNone() || !valueSlice.isNull()) {
        continue;
      }
      auto const keySlice = docSlice.get("seq");
      expectedDocs.emplace(keySlice.getNumber<ptrdiff_t>(), docSlice);
    }

    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value >= null and d.value <= null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(expectedDocs.size() == resultIt.size());

    for (auto const actualDoc : resultIt) {
      auto const resolved = actualDoc.resolveExternals();
      auto const keySlice = resolved.get("seq");
      auto const key = keySlice.getNumber<ptrdiff_t>();

      auto expectedDoc = expectedDocs.find(key);
      REQUIRE(expectedDoc != expectedDocs.end());
      CHECK(0 == arangodb::basics::VelocyPackHelper::compare(expectedDoc->second, resolved, true));
      expectedDocs.erase(expectedDoc);
    }
    CHECK(expectedDocs.empty());
  }

  // d.value >= null and d.value <= null, BM25(), TFIDF(), d.seq DESC
  // (will be converted to d.value >= 0 AND d.value <= 0)
  {
    std::map<ptrdiff_t, arangodb::velocypack::Slice> expectedDocs;
    for (auto const& doc : insertedDocs) {
      arangodb::velocypack::Slice docSlice = doc.slice().resolveExternals();
      auto const valueSlice = docSlice.get("value");
      if (valueSlice.isNone() || !valueSlice.isNull()) {
        continue;
      }
      auto const keySlice = docSlice.get("seq");
      expectedDocs.emplace(keySlice.getNumber<ptrdiff_t>(), docSlice);
    }

    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value >= null and d.value <= null SORT BM25(d), TFIDF(d), d.seq DESC RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(expectedDocs.size() == resultIt.size());

    auto expectedDoc = expectedDocs.rbegin();
    for (auto const actualDoc : resultIt) {
      auto const resolved = actualDoc.resolveExternals();
      CHECK(0 == arangodb::basics::VelocyPackHelper::compare(expectedDoc->second, resolved, true));
      ++expectedDoc;
    }
    CHECK(expectedDoc == expectedDocs.rend());
  }

  // -----------------------------------------------------------------------------
  // --SECTION--                                                     Range(>=, <=)
  // -----------------------------------------------------------------------------

  // d.value >= null and d.value <= null, unordered
  // (will be converted to d.value >= 0 AND d.value <= 0)
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value IN null..null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);
    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());
    CHECK(!resultIt.valid());
  }

  // d.seq >= nullptr AND d.seq <= nullptr, unordered
  // (will be converted to d.seq >= 0 AND d.seq <= 0)
  {
    std::unordered_map<size_t, arangodb::velocypack::Slice> expectedDocs {
      { 0, insertedDocs[7].slice() }, // seq == 0
    };

    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.seq IN null..null RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);

    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    REQUIRE(expectedDocs.size() == resultIt.size());
    CHECK(resultIt.valid());

    for (auto const actualDoc : resultIt) {
      auto const resolved = actualDoc.resolveExternals();
      auto key = resolved.get("seq");
      auto expectedDoc = expectedDocs.find(key.getNumber<size_t>());
      CHECK(expectedDoc != expectedDocs.end());
      CHECK(0 == arangodb::basics::VelocyPackHelper::compare(expectedDoc->second, resolved, true));
      expectedDocs.erase(expectedDoc);
    }
    CHECK(expectedDocs.empty());
  }

  // d.value >= null and d.value <= null, BM25(), TFIDF(), d.seq DESC
  // (will be converted to d.value >= 0 AND d.value <= 0)
  {
    auto queryResult = arangodb::tests::executeQuery(
      vocbase,
      "FOR d IN testView SEARCH d.value IN null..null SORT BM25(d), TFIDF(d), d.seq DESC RETURN d"
    );
    REQUIRE(TRI_ERROR_NO_ERROR == queryResult.code);
    auto result = queryResult.result->slice();
    CHECK(result.isArray());

    arangodb::velocypack::ArrayIterator resultIt(result);
    CHECK(0 == resultIt.size());
    CHECK(!resultIt.valid());
  }
}

// -----------------------------------------------------------------------------
// --SECTION--                                                       END-OF-FILE
// -----------------------------------------------------------------------------