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/**
* Copyright (C) 2013 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.
*/
/**
* This file contains tests for mongo/db/exec/sort.cpp
*/
#include "mongo/db/exec/sort.h"
#include "mongo/db/json.h"
#include "mongo/db/exec/mock_stage.h"
#include "mongo/unittest/unittest.h"
using namespace mongo;
namespace {
TEST(SortStageTest, SortEmptyWorkingSet) {
WorkingSet ws;
// MockStage will be owned by SortStage.
MockStage* ms = new MockStage(&ws);
SortStageParams params;
SortStage sort(params, &ws, ms);
// Check initial EOF state.
ASSERT_TRUE(ms->isEOF());
ASSERT_FALSE(sort.isEOF());
// First call to work() initializes sort key generator.
WorkingSetID id = WorkingSet::INVALID_ID;
PlanStage::StageState state = sort.work(&id);
ASSERT_EQUALS(state, PlanStage::NEED_TIME);
// Second call to work() sorts data in vector.
state = sort.work(&id);
ASSERT_EQUALS(state, PlanStage::NEED_TIME);
// Finally we hit EOF.
state = sort.work(&id);
ASSERT_EQUALS(state, PlanStage::IS_EOF);
ASSERT_TRUE(sort.isEOF());
}
/**
* Test function to verify sort stage.
* SortStageParams will be initialized using patternStr, queryStr and limit.
* inputStr represents the input data set in a BSONObj.
* {input: [doc1, doc2, doc3, ...]}
* expectedStr represents the expected sorted data set.
* {output: [docA, docB, docC, ...]}
*/
void testWork(const char* patternStr, const char* queryStr, int limit,
const char* inputStr, const char* expectedStr) {
// WorkingSet is not owned by stages
// so it's fine to declare
WorkingSet ws;
// MockStage will be owned by SortStage.
MockStage* ms = new MockStage(&ws);
BSONObj inputObj = fromjson(inputStr);
BSONElement inputElt = inputObj.getField("input");
ASSERT(inputElt.isABSONObj());
BSONObjIterator inputIt(inputElt.embeddedObject());
while (inputIt.more()) {
BSONElement elt = inputIt.next();
ASSERT(elt.isABSONObj());
BSONObj obj = elt.embeddedObject();
// Insert obj from input array into working set.
WorkingSetMember wsm;
wsm.state = WorkingSetMember::OWNED_OBJ;
wsm.obj = obj;
ms->pushBack(wsm);
}
// Initialize SortStageParams
// Setting limit to 0 means no limit
SortStageParams params;
params.pattern = fromjson(patternStr);
params.query = fromjson(queryStr);
params.limit = limit;
SortStage sort(params, &ws, ms);
WorkingSetID id = WorkingSet::INVALID_ID;
PlanStage::StageState state = PlanStage::NEED_TIME;
// Keep working sort stage until data is available.
while (state == PlanStage::NEED_TIME) {
state = sort.work(&id);
}
// Child's state should be EOF when sort is ready to advance.
ASSERT_TRUE(ms->isEOF());
// While there's data to be retrieved, state should be equal to ADVANCED.
// Insert documents into BSON document in this format:
// {output: [docA, docB, docC, ...]}
BSONObjBuilder bob;
BSONArrayBuilder arr(bob.subarrayStart("output"));
while (state == PlanStage::ADVANCED) {
WorkingSetMember* member = ws.get(id);
const BSONObj& obj = member->obj;
arr.append(obj);
state = sort.work(&id);
}
arr.doneFast();
BSONObj outputObj = bob.obj();
// Sort stage should be EOF after data is retrieved.
ASSERT_EQUALS(state, PlanStage::IS_EOF);
ASSERT_TRUE(sort.isEOF());
// Finally, we get to compare the sorted results against what we expect.
BSONObj expectedObj = fromjson(expectedStr);
if (outputObj != expectedObj) {
mongoutils::str::stream ss;
// Even though we have the original string representation of the expected output,
// we invoke BSONObj::toString() to get a format consistent with outputObj.
ss << "Unexpected sort result with query=" << queryStr << "; pattern=" << patternStr
<< "; limit=" << limit << ":\n"
<< "Expected: " << expectedObj.toString() << "\n"
<< "Actual: " << outputObj.toString() << "\n";
FAIL(ss);
}
}
//
// Limit values
// The server interprets limit values from the user as follows:
// 0: no limit on query results. This is passed along unchanged to the sort stage.
// >0: soft limit. Also unchanged in sort stage.
// <0: hard limit. Absolute value is stored in parsed query and passed to sort stage.
// The sort stage treats both soft and hard limits in the same manner
//
// Sort without limit
// Implementation should keep all items fetched from child.
//
TEST(SortStageTest, SortAscending) {
testWork("{a: 1}", "{}", 0,
"{input: [{a: 2}, {a: 1}, {a: 3}]}",
"{output: [{a: 1}, {a: 2}, {a: 3}]}");
}
TEST(SortStageTest, SortDescending) {
testWork("{a: -1}", "{}", 0,
"{input: [{a: 2}, {a: 1}, {a: 3}]}",
"{output: [{a: 3}, {a: 2}, {a: 1}]}");
}
TEST(SortStageTest, SortIrrelevantSortKey) {
testWork("{b: 1}", "{}", 0,
"{input: [{a: 2}, {a: 1}, {a: 3}]}",
"{output: [{a: 2}, {a: 1}, {a: 3}]}");
}
//
// Sorting with limit > 1
// Implementation should retain top N items
// and discard the rest.
//
TEST(SortStageTest, SortAscendingWithLimit) {
testWork("{a: 1}", "{}", 2,
"{input: [{a: 2}, {a: 1}, {a: 3}]}",
"{output: [{a: 1}, {a: 2}]}");
}
TEST(SortStageTest, SortDescendingWithLimit) {
testWork("{a: -1}", "{}", 2,
"{input: [{a: 2}, {a: 1}, {a: 3}]}",
"{output: [{a: 3}, {a: 2}]}");
}
//
// Sorting with limit > size of data set
// Implementation should retain top N items
// and discard the rest.
//
TEST(SortStageTest, SortAscendingWithLimitGreaterThanInputSize) {
testWork("{a: 1}", "{}", 10,
"{input: [{a: 2}, {a: 1}, {a: 3}]}",
"{output: [{a: 1}, {a: 2}, {a: 3}]}");
}
TEST(SortStageTest, SortDescendingWithLimitGreaterThanInputSize) {
testWork("{a: -1}", "{}", 10,
"{input: [{a: 2}, {a: 1}, {a: 3}]}",
"{output: [{a: 3}, {a: 2}, {a: 1}]}");
}
//
// Sorting with limit 1
// Implementation should optimize this into a running maximum.
//
TEST(SortStageTest, SortAscendingWithLimitOfOne) {
testWork("{a: 1}", "{}", 1,
"{input: [{a: 2}, {a: 1}, {a: 3}]}",
"{output: [{a: 1}]}");
}
TEST(SortStageTest, SortDescendingWithLimitOfOne) {
testWork("{a: -1}", "{}", 1,
"{input: [{a: 2}, {a: 1}, {a: 3}]}",
"{output: [{a: 3}]}");
}
} // namespace
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