////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2018 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 Tobias Gödderz
/// @author Michael Hackstein
/// @author Heiko Kernbach
/// @author Jan Christoph Uhde
////////////////////////////////////////////////////////////////////////////////

#include "AqlItemBlockHelper.h"
#include "DependencyProxyMock.h"
#include "RowFetcherHelper.h"
#include "gtest/gtest.h"

#include "Aql/AqlItemBlock.h"
#include "Aql/DependencyProxy.h"
#include "Aql/ExecutionBlock.h"
#include "Aql/ExecutorInfos.h"
#include "Aql/InputAqlItemRow.h"
#include "Aql/MultiDependencySingleRowFetcher.h"
#include "Aql/ResourceUsage.h"

#include <velocypack/Builder.h>
#include <velocypack/velocypack-aliases.h>

using namespace arangodb;
using namespace arangodb::aql;

namespace arangodb {
namespace tests {
namespace aql {

class MultiDependencySingleRowFetcherTest : public ::testing::Test {
 protected:
  ResourceMonitor monitor;
  AqlItemBlockManager itemBlockManager;
  ExecutionState state;

  MultiDependencySingleRowFetcherTest() : itemBlockManager(&monitor) {}
};

TEST_F(MultiDependencySingleRowFetcherTest,
       no_blocks_upstream_single_dependency_the_producer_doesnt_wait) {
  VPackBuilder input;
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 0, 1};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  dependencyProxyMock.getDependencyMock(0).shouldReturn(ExecutionState::DONE, nullptr);

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(!row);
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == 1);
}

TEST_F(MultiDependencySingleRowFetcherTest,
       no_blocks_upstream_single_dependency_the_producer_waits) {
  VPackBuilder input;
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 0, 1};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  dependencyProxyMock.getDependencyMock(0)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::DONE, nullptr);

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::WAITING);
    ASSERT_TRUE(!row);

    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(!row);
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == 2);
}

TEST_F(MultiDependencySingleRowFetcherTest,
       single_upstream_block_with_a_single_row_single_dependency_the_producer_returns_done_immediately) {
  VPackBuilder input;
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 1, 1};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  SharedAqlItemBlockPtr block = buildBlock<1>(itemBlockManager, {{42}});
  dependencyProxyMock.getDependencyMock(0).shouldReturn(ExecutionState::DONE,
                                                        std::move(block));

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(row);
    ASSERT_TRUE(row.getNrRegisters() == 1);
    ASSERT_TRUE(row.getValue(0).slice().getInt() == 42);
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == 1);
}

TEST_F(MultiDependencySingleRowFetcherTest,
       single_upstream_block_with_a_single_row_single_dependency_the_producer_returns_hasmore_then_done_with_a_nullptr) {
  VPackBuilder input;
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 1, 1};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  SharedAqlItemBlockPtr block = buildBlock<1>(itemBlockManager, {{42}});
  dependencyProxyMock.getDependencyMock(0)
      .shouldReturn(ExecutionState::HASMORE, std::move(block))
      .andThenReturn(ExecutionState::DONE, nullptr);

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::HASMORE);
    ASSERT_TRUE(row);
    ASSERT_TRUE(row.getNrRegisters() == 1);
    ASSERT_TRUE(row.getValue(0).slice().getInt() == 42);

    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(!row);
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == 2);
}

TEST_F(MultiDependencySingleRowFetcherTest,
       single_upstream_block_with_a_single_row_single_dependency_the_producer_waits_then_returns_done) {
  VPackBuilder input;
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 1, 1};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  SharedAqlItemBlockPtr block = buildBlock<1>(itemBlockManager, {{42}});
  dependencyProxyMock.getDependencyMock(0)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::DONE, std::move(block));

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::WAITING);
    ASSERT_TRUE(!row);

    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(row);
    ASSERT_TRUE(row.getNrRegisters() == 1);
    ASSERT_TRUE(row.getValue(0).slice().getInt() == 42);
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == 2);
}

TEST_F(MultiDependencySingleRowFetcherTest,
       single_upstream_block_with_a_single_row_single_dependency_the_producer_waits_returns_hasmore_then_done) {
  VPackBuilder input;
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 1, 1};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  SharedAqlItemBlockPtr block = buildBlock<1>(itemBlockManager, {{42}});
  dependencyProxyMock.getDependencyMock(0)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(block))
      .andThenReturn(ExecutionState::DONE, nullptr);

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::WAITING);
    ASSERT_TRUE(!row);

    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::HASMORE);
    ASSERT_TRUE(row);
    ASSERT_TRUE(row.getNrRegisters() == 1);
    ASSERT_TRUE(row.getValue(0).slice().getInt() == 42);

    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(!row);
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == 3);
}

// TODO the following tests should be simplified, a simple output
// specification should be compared with the actual output.

TEST_F(MultiDependencySingleRowFetcherTest,
       multiple_blocks_upstream_single_dependency_the_producer_doesnt_wait) {
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 1, 1};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  // three 1-column matrices with 3, 2 and 1 rows, respectively
  SharedAqlItemBlockPtr block1 = buildBlock<1>(itemBlockManager, {{{1}}, {{2}}, {{3}}}),
                        block2 = buildBlock<1>(itemBlockManager, {{{4}}, {{5}}}),
                        block3 = buildBlock<1>(itemBlockManager, {{{6}}});
  dependencyProxyMock.getDependencyMock(0)
      .shouldReturn(ExecutionState::HASMORE, std::move(block1))
      .andThenReturn(ExecutionState::HASMORE, std::move(block2))
      .andThenReturn(ExecutionState::DONE, std::move(block3));

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    int64_t rowIdxAndValue;
    for (rowIdxAndValue = 1; rowIdxAndValue <= 5; rowIdxAndValue++) {
      std::tie(state, row) = testee.fetchRowForDependency(0);
      ASSERT_TRUE(state == ExecutionState::HASMORE);
      ASSERT_TRUE(row);
      ASSERT_TRUE(row.getNrRegisters() == 1);
      ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
    }
    rowIdxAndValue = 6;
    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(row);
    ASSERT_TRUE(row.getNrRegisters() == 1);
    ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == 3);
}

TEST_F(MultiDependencySingleRowFetcherTest,
       multiple_blocks_upstream_single_dependency_the_producer_waits) {
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 1, 1};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  // three 1-column matrices with 3, 2 and 1 rows, respectively
  SharedAqlItemBlockPtr block1 = buildBlock<1>(itemBlockManager, {{{1}}, {{2}}, {{3}}}),
                        block2 = buildBlock<1>(itemBlockManager, {{{4}}, {{5}}}),
                        block3 = buildBlock<1>(itemBlockManager, {{{6}}});
  dependencyProxyMock.getDependencyMock(0)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(block1))
      .andThenReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(block2))
      .andThenReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::DONE, std::move(block3));

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    int64_t rowIdxAndValue;
    for (rowIdxAndValue = 1; rowIdxAndValue <= 5; rowIdxAndValue++) {
      if (rowIdxAndValue == 1 || rowIdxAndValue == 4) {
        // wait at the beginning of the 1st and 2nd block
        std::tie(state, row) = testee.fetchRowForDependency(0);
        ASSERT_TRUE(state == ExecutionState::WAITING);
        ASSERT_TRUE(!row);
      }
      std::tie(state, row) = testee.fetchRowForDependency(0);
      ASSERT_TRUE(state == ExecutionState::HASMORE);
      ASSERT_TRUE(row);
      ASSERT_TRUE(row.getNrRegisters() == 1);
      ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
    }
    rowIdxAndValue = 6;
    // wait at the beginning of the 3rd block
    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::WAITING);
    ASSERT_TRUE(!row);
    // last row and DONE
    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(row);
    ASSERT_TRUE(row.getNrRegisters() == 1);
    ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == 6);
}

TEST_F(MultiDependencySingleRowFetcherTest,
       multiple_blocks_upstream_single_dependency_the_producer_the_producer_waits_and_doesnt_return_done_asap) {
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 1, 1};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  // three 1-column matrices with 3, 2 and 1 rows, respectively
  SharedAqlItemBlockPtr block1 = buildBlock<1>(itemBlockManager, {{{1}}, {{2}}, {{3}}}),
                        block2 = buildBlock<1>(itemBlockManager, {{{4}}, {{5}}}),
                        block3 = buildBlock<1>(itemBlockManager, {{{6}}});
  dependencyProxyMock.getDependencyMock(0)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(block1))
      .andThenReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(block2))
      .andThenReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(block3))
      .andThenReturn(ExecutionState::DONE, nullptr);

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    for (int64_t rowIdxAndValue = 1; rowIdxAndValue <= 6; rowIdxAndValue++) {
      if (rowIdxAndValue == 1 || rowIdxAndValue == 4 || rowIdxAndValue == 6) {
        // wait at the beginning of the 1st, 2nd and 3rd block
        std::tie(state, row) = testee.fetchRowForDependency(0);
        ASSERT_TRUE(state == ExecutionState::WAITING);
        ASSERT_TRUE(!row);
      }
      std::tie(state, row) = testee.fetchRowForDependency(0);
      ASSERT_TRUE(state == ExecutionState::HASMORE);
      ASSERT_TRUE(row);
      ASSERT_TRUE(row.getNrRegisters() == 1);
      ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
    }
    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(!row);
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == 7);
}

/*********************
 *  Multi Dependencies
 *********************/

TEST_F(MultiDependencySingleRowFetcherTest,
       no_blocks_upstream_multiple_dependencies_the_producers_dont_wait) {
  VPackBuilder input;
  size_t numDeps = 3;
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 0, numDeps};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  for (size_t i = 0; i < numDeps; ++i) {
    dependencyProxyMock.getDependencyMock(i).shouldReturn(ExecutionState::DONE, nullptr);
  }

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    for (size_t i = 0; i < numDeps; ++i) {
      std::tie(state, row) = testee.fetchRowForDependency(i);
      ASSERT_TRUE(state == ExecutionState::DONE);
      ASSERT_TRUE(!row);
    }
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == numDeps);
}

TEST_F(MultiDependencySingleRowFetcherTest,
       no_blocks_upstream_multiple_dependencies_the_producers_wait) {
  VPackBuilder input;
  size_t numDeps = 3;
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 0, numDeps};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  for (size_t i = 0; i < numDeps; ++i) {
    dependencyProxyMock.getDependencyMock(i)
        .shouldReturn(ExecutionState::WAITING, nullptr)
        .andThenReturn(ExecutionState::DONE, nullptr);
  }

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    for (size_t i = 0; i < numDeps; ++i) {
      std::tie(state, row) = testee.fetchRowForDependency(i);
      ASSERT_TRUE(state == ExecutionState::WAITING);
      ASSERT_TRUE(!row);
    }

    for (size_t i = 0; i < numDeps; ++i) {
      std::tie(state, row) = testee.fetchRowForDependency(i);
      ASSERT_TRUE(state == ExecutionState::DONE);
      ASSERT_TRUE(!row);
    }
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == 2 * numDeps);
}

TEST_F(MultiDependencySingleRowFetcherTest,
       single_upstream_block_with_a_single_row_multi_dependency_the_producer_returns_done_immediately) {
  VPackBuilder input;
  size_t numDeps = 3;
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 1, numDeps};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  SharedAqlItemBlockPtr blockDep1 = buildBlock<1>(itemBlockManager, {{42}});
  SharedAqlItemBlockPtr blockDep2 = buildBlock<1>(itemBlockManager, {{23}});
  SharedAqlItemBlockPtr blockDep3 = buildBlock<1>(itemBlockManager, {{1337}});
  dependencyProxyMock.getDependencyMock(0).shouldReturn(ExecutionState::DONE,
                                                        std::move(blockDep1));
  dependencyProxyMock.getDependencyMock(1).shouldReturn(ExecutionState::DONE,
                                                        std::move(blockDep2));
  dependencyProxyMock.getDependencyMock(2).shouldReturn(ExecutionState::DONE,
                                                        std::move(blockDep3));

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    for (size_t i = 0; i < numDeps; ++i) {
      std::tie(state, row) = testee.fetchRowForDependency(i);
      ASSERT_TRUE(state == ExecutionState::DONE);
      ASSERT_TRUE(row);
      ASSERT_TRUE(row.getNrRegisters() == 1);
      if (i == 0) {
        ASSERT_TRUE(row.getValue(0).slice().getInt() == 42);
      } else if (i == 1) {
        ASSERT_TRUE(row.getValue(0).slice().getInt() == 23);
      } else {
        ASSERT_TRUE(row.getValue(0).slice().getInt() == 1337);
      }
    }
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == numDeps);
}

TEST_F(MultiDependencySingleRowFetcherTest,
       single_upstream_block_with_a_single_row_multi_dependency_the_producer_returns_hasmore_then_done_with_a_nullptr) {
  VPackBuilder input;
  size_t numDeps = 3;
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 1, numDeps};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  SharedAqlItemBlockPtr blockDep1 = buildBlock<1>(itemBlockManager, {{42}});
  SharedAqlItemBlockPtr blockDep2 = buildBlock<1>(itemBlockManager, {{23}});
  SharedAqlItemBlockPtr blockDep3 = buildBlock<1>(itemBlockManager, {{1337}});
  dependencyProxyMock.getDependencyMock(0)
      .shouldReturn(ExecutionState::HASMORE, std::move(blockDep1))
      .andThenReturn(ExecutionState::DONE, nullptr);
  dependencyProxyMock.getDependencyMock(1)
      .shouldReturn(ExecutionState::HASMORE, std::move(blockDep2))
      .andThenReturn(ExecutionState::DONE, nullptr);
  dependencyProxyMock.getDependencyMock(2)
      .shouldReturn(ExecutionState::HASMORE, std::move(blockDep3))
      .andThenReturn(ExecutionState::DONE, nullptr);

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    for (size_t i = 0; i < numDeps; ++i) {
      std::tie(state, row) = testee.fetchRowForDependency(i);
      ASSERT_TRUE(state == ExecutionState::HASMORE);
      ASSERT_TRUE(row);
      ASSERT_TRUE(row.getNrRegisters() == 1);
      if (i == 0) {
        ASSERT_TRUE(row.getValue(0).slice().getInt() == 42);
      } else if (i == 1) {
        ASSERT_TRUE(row.getValue(0).slice().getInt() == 23);
      } else {
        ASSERT_TRUE(row.getValue(0).slice().getInt() == 1337);
      }
    }

    for (size_t i = 0; i < numDeps; ++i) {
      std::tie(state, row) = testee.fetchRowForDependency(i);
      ASSERT_TRUE(state == ExecutionState::DONE);
      ASSERT_TRUE(!row);
    }
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == 2 * numDeps);
}

TEST_F(MultiDependencySingleRowFetcherTest,
       single_upstream_block_with_a_single_row_multi_dependency_the_producer_waits_then_returns_done) {
  VPackBuilder input;
  size_t numDeps = 3;
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 1, numDeps};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  SharedAqlItemBlockPtr blockDep1 = buildBlock<1>(itemBlockManager, {{42}});
  SharedAqlItemBlockPtr blockDep2 = buildBlock<1>(itemBlockManager, {{23}});
  SharedAqlItemBlockPtr blockDep3 = buildBlock<1>(itemBlockManager, {{1337}});
  dependencyProxyMock.getDependencyMock(0)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::DONE, std::move(blockDep1));
  dependencyProxyMock.getDependencyMock(1)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::DONE, std::move(blockDep2));
  dependencyProxyMock.getDependencyMock(2)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::DONE, std::move(blockDep3));

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    for (size_t i = 0; i < numDeps; ++i) {
      std::tie(state, row) = testee.fetchRowForDependency(i);
      ASSERT_TRUE(state == ExecutionState::WAITING);
      ASSERT_TRUE(!row);
    }

    for (size_t i = 0; i < numDeps; ++i) {
      std::tie(state, row) = testee.fetchRowForDependency(i);
      ASSERT_TRUE(state == ExecutionState::DONE);
      ASSERT_TRUE(row);
      ASSERT_TRUE(row.getNrRegisters() == 1);
      if (i == 0) {
        ASSERT_TRUE(row.getValue(0).slice().getInt() == 42);
      } else if (i == 1) {
        ASSERT_TRUE(row.getValue(0).slice().getInt() == 23);
      } else {
        ASSERT_TRUE(row.getValue(0).slice().getInt() == 1337);
      }
    }
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == 2 * numDeps);
}

TEST_F(MultiDependencySingleRowFetcherTest,
       single_upstream_block_with_a_single_row_multi_dependency_the_producer_waits_returns_more_then_done) {
  VPackBuilder input;
  size_t numDeps = 3;
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 1, numDeps};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  SharedAqlItemBlockPtr blockDep1 = buildBlock<1>(itemBlockManager, {{42}});
  SharedAqlItemBlockPtr blockDep2 = buildBlock<1>(itemBlockManager, {{23}});
  SharedAqlItemBlockPtr blockDep3 = buildBlock<1>(itemBlockManager, {{1337}});
  dependencyProxyMock.getDependencyMock(0)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(blockDep1))
      .andThenReturn(ExecutionState::DONE, nullptr);
  dependencyProxyMock.getDependencyMock(1)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(blockDep2))
      .andThenReturn(ExecutionState::DONE, nullptr);
  dependencyProxyMock.getDependencyMock(2)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(blockDep3))
      .andThenReturn(ExecutionState::DONE, nullptr);

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    for (size_t i = 0; i < numDeps; ++i) {
      std::tie(state, row) = testee.fetchRowForDependency(i);
      ASSERT_TRUE(state == ExecutionState::WAITING);
      ASSERT_TRUE(!row);
    }

    for (size_t i = 0; i < numDeps; ++i) {
      std::tie(state, row) = testee.fetchRowForDependency(i);
      ASSERT_TRUE(state == ExecutionState::HASMORE);
      ASSERT_TRUE(row);
      ASSERT_TRUE(row.getNrRegisters() == 1);
      if (i == 0) {
        ASSERT_TRUE(row.getValue(0).slice().getInt() == 42);
      } else if (i == 1) {
        ASSERT_TRUE(row.getValue(0).slice().getInt() == 23);
      } else {
        ASSERT_TRUE(row.getValue(0).slice().getInt() == 1337);
      }
    }

    for (size_t i = 0; i < numDeps; ++i) {
      std::tie(state, row) = testee.fetchRowForDependency(i);
      ASSERT_TRUE(state == ExecutionState::DONE);
      ASSERT_TRUE(!row);
    }
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == 3 * numDeps);
}

// TODO the following tests should be simplified, a simple output
// specification should be compared with the actual output.

TEST_F(MultiDependencySingleRowFetcherTest,
       multiple_blocks_upstream_multiple_dependencies_the_producer_does_not_wait) {
  size_t numDeps = 3;
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 1, numDeps};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  // three 1-column matrices with 3, 2 and 1 rows, respectively
  SharedAqlItemBlockPtr block1Dep1 =
                            buildBlock<1>(itemBlockManager, {{{1}}, {{2}}, {{3}}}),
                        block2Dep1 = buildBlock<1>(itemBlockManager, {{{4}}, {{5}}}),
                        block3Dep1 = buildBlock<1>(itemBlockManager, {{{6}}});
  // two 1-column matrices with 1 and 2 rows, respectively
  SharedAqlItemBlockPtr block1Dep2 = buildBlock<1>(itemBlockManager, {{{7}}}),
                        block2Dep2 = buildBlock<1>(itemBlockManager, {{{8}}, {{9}}});
  // single 1-column matrices with 2 rows
  SharedAqlItemBlockPtr block1Dep3 = buildBlock<1>(itemBlockManager, {{{10}}, {{11}}});
  dependencyProxyMock.getDependencyMock(0)
      .shouldReturn(ExecutionState::HASMORE, std::move(block1Dep1))
      .andThenReturn(ExecutionState::HASMORE, std::move(block2Dep1))
      .andThenReturn(ExecutionState::DONE, std::move(block3Dep1));
  dependencyProxyMock.getDependencyMock(1)
      .shouldReturn(ExecutionState::HASMORE, std::move(block1Dep2))
      .andThenReturn(ExecutionState::DONE, std::move(block2Dep2));
  dependencyProxyMock.getDependencyMock(2).shouldReturn(ExecutionState::DONE,
                                                        std::move(block1Dep3));

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    int64_t rowIdxAndValue;
    for (rowIdxAndValue = 1; rowIdxAndValue <= 5; rowIdxAndValue++) {
      std::tie(state, row) = testee.fetchRowForDependency(0);
      ASSERT_TRUE(state == ExecutionState::HASMORE);
      ASSERT_TRUE(row);
      ASSERT_TRUE(row.getNrRegisters() == 1);
      ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
    }
    rowIdxAndValue = 6;
    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(row);
    ASSERT_TRUE(row.getNrRegisters() == 1);
    ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);

    for (rowIdxAndValue = 7; rowIdxAndValue <= 8; rowIdxAndValue++) {
      std::tie(state, row) = testee.fetchRowForDependency(1);
      ASSERT_TRUE(state == ExecutionState::HASMORE);
      ASSERT_TRUE(row);
      ASSERT_TRUE(row.getNrRegisters() == 1);
      ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
    }
    rowIdxAndValue = 9;
    std::tie(state, row) = testee.fetchRowForDependency(1);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(row);
    ASSERT_TRUE(row.getNrRegisters() == 1);
    ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);

    for (rowIdxAndValue = 10; rowIdxAndValue <= 10; rowIdxAndValue++) {
      std::tie(state, row) = testee.fetchRowForDependency(2);
      ASSERT_TRUE(state == ExecutionState::HASMORE);
      ASSERT_TRUE(row);
      ASSERT_TRUE(row.getNrRegisters() == 1);
      ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
    }
    rowIdxAndValue = 11;
    std::tie(state, row) = testee.fetchRowForDependency(2);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(row);
    ASSERT_TRUE(row.getNrRegisters() == 1);
    ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == 3 + 2 + 1);
}

TEST_F(MultiDependencySingleRowFetcherTest,
       multiple_blocks_upstream_multiple_dependencies_the_producer_waits) {
  size_t numDeps = 3;
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 1, numDeps};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  // three 1-column matrices with 3, 2 and 1 rows, respectively
  SharedAqlItemBlockPtr block1Dep1 =
                            buildBlock<1>(itemBlockManager, {{{1}}, {{2}}, {{3}}}),
                        block2Dep1 = buildBlock<1>(itemBlockManager, {{{4}}, {{5}}}),
                        block3Dep1 = buildBlock<1>(itemBlockManager, {{{6}}});
  // two 1-column matrices with 1 and 2 rows, respectively
  SharedAqlItemBlockPtr block1Dep2 = buildBlock<1>(itemBlockManager, {{{7}}}),
                        block2Dep2 = buildBlock<1>(itemBlockManager, {{{8}}, {{9}}});
  // single 1-column matrices with 2 rows
  SharedAqlItemBlockPtr block1Dep3 = buildBlock<1>(itemBlockManager, {{{10}}, {{11}}});
  dependencyProxyMock.getDependencyMock(0)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(block1Dep1))
      .andThenReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(block2Dep1))
      .andThenReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::DONE, std::move(block3Dep1));
  dependencyProxyMock.getDependencyMock(1)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(block1Dep2))
      .andThenReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::DONE, std::move(block2Dep2));
  dependencyProxyMock.getDependencyMock(2)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::DONE, std::move(block1Dep3));

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    int64_t rowIdxAndValue;
    for (rowIdxAndValue = 1; rowIdxAndValue <= 5; rowIdxAndValue++) {
      if (rowIdxAndValue == 1 || rowIdxAndValue == 4) {
        // wait at the beginning of the 1st and 2nd block
        std::tie(state, row) = testee.fetchRowForDependency(0);
        ASSERT_TRUE(state == ExecutionState::WAITING);
        ASSERT_TRUE(!row);
      }
      std::tie(state, row) = testee.fetchRowForDependency(0);
      ASSERT_TRUE(state == ExecutionState::HASMORE);
      ASSERT_TRUE(row);
      ASSERT_TRUE(row.getNrRegisters() == 1);
      ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
    }
    rowIdxAndValue = 6;
    // wait at the beginning of the 3rd block
    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::WAITING);
    ASSERT_TRUE(!row);
    // last row and DONE
    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(row);
    ASSERT_TRUE(row.getNrRegisters() == 1);
    ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);

    for (rowIdxAndValue = 7; rowIdxAndValue <= 8; rowIdxAndValue++) {
      if (rowIdxAndValue == 7 || rowIdxAndValue == 8) {
        // wait at the beginning of the 1st and 2nd block
        std::tie(state, row) = testee.fetchRowForDependency(1);
        ASSERT_TRUE(state == ExecutionState::WAITING);
        ASSERT_TRUE(!row);
      }
      std::tie(state, row) = testee.fetchRowForDependency(1);
      ASSERT_TRUE(state == ExecutionState::HASMORE);
      ASSERT_TRUE(row);
      ASSERT_TRUE(row.getNrRegisters() == 1);
      ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
    }
    rowIdxAndValue = 9;
    std::tie(state, row) = testee.fetchRowForDependency(1);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(row);
    ASSERT_TRUE(row.getNrRegisters() == 1);
    ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);

    for (rowIdxAndValue = 10; rowIdxAndValue <= 10; rowIdxAndValue++) {
      if (rowIdxAndValue == 10) {
        // wait at the beginning of the 1st and 2nd block
        std::tie(state, row) = testee.fetchRowForDependency(2);
        ASSERT_TRUE(state == ExecutionState::WAITING);
        ASSERT_TRUE(!row);
      }
      std::tie(state, row) = testee.fetchRowForDependency(2);
      ASSERT_TRUE(state == ExecutionState::HASMORE);
      ASSERT_TRUE(row);
      ASSERT_TRUE(row.getNrRegisters() == 1);
      ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
    }
    rowIdxAndValue = 11;
    std::tie(state, row) = testee.fetchRowForDependency(2);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(row);
    ASSERT_TRUE(row.getNrRegisters() == 1);
    ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == 12);
}

TEST_F(MultiDependencySingleRowFetcherTest,
       multiple_blocks_upstream_multiple_dependencies_the_producer_waits_and_doesnt_return_done_asap) {
  size_t numDeps = 3;
  MultiDependencyProxyMock<false> dependencyProxyMock{monitor, 1, numDeps};
  InputAqlItemRow row{CreateInvalidInputRowHint{}};
  // three 1-column matrices with 3, 2 and 1 rows, respectively
  SharedAqlItemBlockPtr block1Dep1 =
                            buildBlock<1>(itemBlockManager, {{{1}}, {{2}}, {{3}}}),
                        block2Dep1 = buildBlock<1>(itemBlockManager, {{{4}}, {{5}}}),
                        block3Dep1 = buildBlock<1>(itemBlockManager, {{{6}}});
  // two 1-column matrices with 1 and 2 rows, respectively
  SharedAqlItemBlockPtr block1Dep2 = buildBlock<1>(itemBlockManager, {{{7}}}),
                        block2Dep2 = buildBlock<1>(itemBlockManager, {{{8}}, {{9}}});
  // single 1-column matrices with 2 rows
  SharedAqlItemBlockPtr block1Dep3 = buildBlock<1>(itemBlockManager, {{{10}}, {{11}}});
  dependencyProxyMock.getDependencyMock(0)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(block1Dep1))
      .andThenReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(block2Dep1))
      .andThenReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(block3Dep1))
      .andThenReturn(ExecutionState::DONE, nullptr);
  dependencyProxyMock.getDependencyMock(1)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(block1Dep2))
      .andThenReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(block2Dep2))
      .andThenReturn(ExecutionState::DONE, nullptr);
  dependencyProxyMock.getDependencyMock(2)
      .shouldReturn(ExecutionState::WAITING, nullptr)
      .andThenReturn(ExecutionState::HASMORE, std::move(block1Dep3))
      .andThenReturn(ExecutionState::DONE, nullptr);

  {
    MultiDependencySingleRowFetcher testee(dependencyProxyMock);

    testee.initDependencies();

    int64_t rowIdxAndValue;
    for (rowIdxAndValue = 1; rowIdxAndValue <= 5; rowIdxAndValue++) {
      if (rowIdxAndValue == 1 || rowIdxAndValue == 4) {
        // wait at the beginning of the 1st and 2nd block
        std::tie(state, row) = testee.fetchRowForDependency(0);
        ASSERT_TRUE(state == ExecutionState::WAITING);
        ASSERT_TRUE(!row);
      }
      std::tie(state, row) = testee.fetchRowForDependency(0);
      ASSERT_TRUE(state == ExecutionState::HASMORE);
      ASSERT_TRUE(row);
      ASSERT_TRUE(row.getNrRegisters() == 1);
      ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
    }
    rowIdxAndValue = 6;
    // wait at the beginning of the 3rd block
    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::WAITING);
    ASSERT_TRUE(!row);
    // last row and DONE
    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::HASMORE);
    ASSERT_TRUE(row);
    ASSERT_TRUE(row.getNrRegisters() == 1);
    ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
    std::tie(state, row) = testee.fetchRowForDependency(0);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(!row);

    for (rowIdxAndValue = 7; rowIdxAndValue <= 8; rowIdxAndValue++) {
      if (rowIdxAndValue == 7 || rowIdxAndValue == 8) {
        // wait at the beginning of the 1st and 2nd block
        std::tie(state, row) = testee.fetchRowForDependency(1);
        ASSERT_TRUE(state == ExecutionState::WAITING);
        ASSERT_TRUE(!row);
      }
      std::tie(state, row) = testee.fetchRowForDependency(1);
      ASSERT_TRUE(state == ExecutionState::HASMORE);
      ASSERT_TRUE(row);
      ASSERT_TRUE(row.getNrRegisters() == 1);
      ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
    }
    rowIdxAndValue = 9;
    std::tie(state, row) = testee.fetchRowForDependency(1);
    ASSERT_TRUE(state == ExecutionState::HASMORE);
    ASSERT_TRUE(row);
    ASSERT_TRUE(row.getNrRegisters() == 1);
    ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
    std::tie(state, row) = testee.fetchRowForDependency(1);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(!row);

    for (rowIdxAndValue = 10; rowIdxAndValue <= 10; rowIdxAndValue++) {
      if (rowIdxAndValue == 10) {
        // wait at the beginning of the 1st and 2nd block
        std::tie(state, row) = testee.fetchRowForDependency(2);
        ASSERT_TRUE(state == ExecutionState::WAITING);
        ASSERT_TRUE(!row);
      }
      std::tie(state, row) = testee.fetchRowForDependency(2);
      ASSERT_TRUE(state == ExecutionState::HASMORE);
      ASSERT_TRUE(row);
      ASSERT_TRUE(row.getNrRegisters() == 1);
      ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
    }
    rowIdxAndValue = 11;
    std::tie(state, row) = testee.fetchRowForDependency(2);
    ASSERT_TRUE(state == ExecutionState::HASMORE);
    ASSERT_TRUE(row);
    ASSERT_TRUE(row.getNrRegisters() == 1);
    ASSERT_TRUE(row.getValue(0).slice().getInt() == rowIdxAndValue);
    std::tie(state, row) = testee.fetchRowForDependency(2);
    ASSERT_TRUE(state == ExecutionState::DONE);
    ASSERT_TRUE(!row);
  }  // testee is destroyed here
  // testee must be destroyed before verify, because it may call returnBlock
  // in the destructor
  ASSERT_TRUE(dependencyProxyMock.allBlocksFetched());
  ASSERT_TRUE(dependencyProxyMock.numFetchBlockCalls() == 15);
}

}  // namespace aql
}  // namespace tests
}  // namespace arangodb