SERVER-19355 add skip support to the new find/getMore path in mongos

1 files changed, 153 insertions, 0 deletions

diff --git a/src/mongo/s/query/router_stage_skip_test.cpp b/src/mongo/s/query/router_stage_skip_test.cpp
new file mode 100644
index 00000000000..e0116136c2f
--- /dev/null
+++ b/src/mongo/s/query/router_stage_skip_test.cpp
@@ -0,0 +1,153 @@
+/**
+ *    Copyright 2015 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#include "mongo/platform/basic.h"
+
+#include "mongo/s/query/router_stage_skip.h"
+
+#include "mongo/bson/bsonobj.h"
+#include "mongo/bson/bsonobjbuilder.h"
+#include "mongo/s/query/router_stage_mock.h"
+#include "mongo/stdx/memory.h"
+#include "mongo/unittest/unittest.h"
+
+namespace mongo {
+
+namespace {
+
+TEST(RouterStageSkipTest, SkipIsOne) {
+    auto mockStage = stdx::make_unique<RouterStageMock>();
+    mockStage->queueResult(BSON("a" << 1));
+    mockStage->queueResult(BSON("a" << 2));
+    mockStage->queueResult(BSON("a" << 3));
+
+    auto skipStage = stdx::make_unique<RouterStageSkip>(std::move(mockStage), 1);
+
+    auto firstResult = skipStage->next();
+    ASSERT_OK(firstResult.getStatus());
+    ASSERT(firstResult.getValue());
+    ASSERT_EQ(*firstResult.getValue(), BSON("a" << 2));
+
+    auto secondResult = skipStage->next();
+    ASSERT_OK(secondResult.getStatus());
+    ASSERT(secondResult.getValue());
+    ASSERT_EQ(*secondResult.getValue(), BSON("a" << 3));
+
+    // Once end-of-stream is reached, the skip stage should keep returning boost::none.
+    auto thirdResult = skipStage->next();
+    ASSERT_OK(thirdResult.getStatus());
+    ASSERT(!thirdResult.getValue());
+
+    auto fourthResult = skipStage->next();
+    ASSERT_OK(thirdResult.getStatus());
+    ASSERT(!thirdResult.getValue());
+}
+
+TEST(RouterStageSkipTest, SkipIsThree) {
+    auto mockStage = stdx::make_unique<RouterStageMock>();
+    mockStage->queueResult(BSON("a" << 1));
+    mockStage->queueResult(BSON("a" << 2));
+    mockStage->queueResult(BSON("a" << 3));
+    mockStage->queueResult(BSON("a" << 4));
+
+    auto skipStage = stdx::make_unique<RouterStageSkip>(std::move(mockStage), 3);
+
+    auto firstResult = skipStage->next();
+    ASSERT_OK(firstResult.getStatus());
+    ASSERT(firstResult.getValue());
+    ASSERT_EQ(*firstResult.getValue(), BSON("a" << 4));
+
+    auto secondResult = skipStage->next();
+    ASSERT_OK(secondResult.getStatus());
+    ASSERT(!secondResult.getValue());
+}
+
+TEST(RouterStageSkipTest, SkipEqualToResultSetSize) {
+    auto mockStage = stdx::make_unique<RouterStageMock>();
+    mockStage->queueResult(BSON("a" << 1));
+    mockStage->queueResult(BSON("a" << 2));
+    mockStage->queueResult(BSON("a" << 3));
+
+    auto skipStage = stdx::make_unique<RouterStageSkip>(std::move(mockStage), 3);
+
+    auto firstResult = skipStage->next();
+    ASSERT_OK(firstResult.getStatus());
+    ASSERT(!firstResult.getValue());
+}
+
+TEST(RouterStageSkipTest, SkipExceedsResultSetSize) {
+    auto mockStage = stdx::make_unique<RouterStageMock>();
+    mockStage->queueResult(BSON("a" << 1));
+    mockStage->queueResult(BSON("a" << 2));
+    mockStage->queueResult(BSON("a" << 3));
+
+    auto skipStage = stdx::make_unique<RouterStageSkip>(std::move(mockStage), 100);
+
+    auto firstResult = skipStage->next();
+    ASSERT_OK(firstResult.getStatus());
+    ASSERT(!firstResult.getValue());
+}
+
+TEST(RouterStageSkipTest, ErrorWhileSkippingResults) {
+    auto mockStage = stdx::make_unique<RouterStageMock>();
+    mockStage->queueResult(BSON("a" << 1));
+    mockStage->queueError(Status(ErrorCodes::BadValue, "bad thing happened"));
+    mockStage->queueResult(BSON("a" << 2));
+    mockStage->queueResult(BSON("a" << 3));
+
+    auto skipStage = stdx::make_unique<RouterStageSkip>(std::move(mockStage), 2);
+
+    auto firstResult = skipStage->next();
+    ASSERT_NOT_OK(firstResult.getStatus());
+    ASSERT_EQ(firstResult.getStatus(), ErrorCodes::BadValue);
+    ASSERT_EQ(firstResult.getStatus().reason(), "bad thing happened");
+}
+
+TEST(RouterStageSkipTest, ErrorAfterSkippingResults) {
+    auto mockStage = stdx::make_unique<RouterStageMock>();
+    mockStage->queueResult(BSON("a" << 1));
+    mockStage->queueResult(BSON("a" << 2));
+    mockStage->queueResult(BSON("a" << 3));
+    mockStage->queueError(Status(ErrorCodes::BadValue, "bad thing happened"));
+
+    auto skipStage = stdx::make_unique<RouterStageSkip>(std::move(mockStage), 2);
+
+    auto firstResult = skipStage->next();
+    ASSERT_OK(firstResult.getStatus());
+    ASSERT(firstResult.getValue());
+    ASSERT_EQ(*firstResult.getValue(), BSON("a" << 3));
+
+    auto secondResult = skipStage->next();
+    ASSERT_NOT_OK(secondResult.getStatus());
+    ASSERT_EQ(secondResult.getStatus(), ErrorCodes::BadValue);
+    ASSERT_EQ(secondResult.getStatus().reason(), "bad thing happened");
+}
+
+}  // namespace
+
+}  // namespace mongo