fakequeryservice.go

/*
Copyright 2017 Google Inc.

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 agreedto 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.
*/

package tabletconntest

import (
	"errors"
	"fmt"
	"reflect"
	"testing"

	"golang.org/x/net/context"

	"github.com/golang/protobuf/proto"
	"vitess.io/vitess/go/sqltypes"
	"vitess.io/vitess/go/vt/callerid"

	querypb "vitess.io/vitess/go/vt/proto/query"
	topodatapb "vitess.io/vitess/go/vt/proto/topodata"
	vtrpcpb "vitess.io/vitess/go/vt/proto/vtrpc"
)

// FakeQueryService implements a programmable fake for the query service
// server side.
type FakeQueryService struct {
	t              *testing.T
	TestingGateway bool

	// these fields are used to simulate and synchronize on errors
	HasError      bool
	HasBeginError bool
	TabletError   error
	ErrorWait     chan struct{}

	// these fields are used to simulate and synchronize on panics
	Panics                   bool
	StreamExecutePanicsEarly bool
	UpdateStreamPanicsEarly  bool
	PanicWait                chan struct{}

	// ExpectedTransactionID is what transactionID to expect for Execute
	ExpectedTransactionID int64

	// StreamHealthResponse is what we return for StreamHealth.
	// If not set, return TestStreamHealthStreamHealthResponse
	StreamHealthResponse *querypb.StreamHealthResponse
}

// Close is a no-op.
func (f *FakeQueryService) Close(ctx context.Context) error {
	return nil
}

// HandlePanic is part of the queryservice.QueryService interface
func (f *FakeQueryService) HandlePanic(err *error) {
	if x := recover(); x != nil {
		*err = fmt.Errorf("caught test panic: %v", x)
	}
}

// TestTarget is the target we use for this test
var TestTarget = &querypb.Target{
	Keyspace:   "test_keyspace",
	Shard:      "test_shard",
	TabletType: topodatapb.TabletType_REPLICA,
}

// TestCallerID is a test caller id.
var TestCallerID = &vtrpcpb.CallerID{
	Principal:    "test_principal",
	Component:    "test_component",
	Subcomponent: "test_subcomponent",
}

// TestVTGateCallerID is a test vtgate caller id.
var TestVTGateCallerID = &querypb.VTGateCallerID{
	Username: "test_username",
}

// TestExecuteOptions is a test execute options.
var TestExecuteOptions = &querypb.ExecuteOptions{
	IncludedFields:    querypb.ExecuteOptions_TYPE_ONLY,
	IncludeEventToken: true,
	CompareEventToken: &querypb.EventToken{
		Timestamp: 9876,
		Shard:     "ssss",
		Position:  "pppp",
	},
	ClientFoundRows: true,
}

// TestAsTransaction is a test 'asTransaction' flag.
const TestAsTransaction bool = true

func (f *FakeQueryService) checkTargetCallerID(ctx context.Context, name string, target *querypb.Target) {
	if !proto.Equal(target, TestTarget) {
		f.t.Errorf("invalid Target for %v: got %#v expected %#v", name, target, TestTarget)
	}

	ef := callerid.EffectiveCallerIDFromContext(ctx)
	if ef == nil {
		f.t.Errorf("no effective caller id for %v", name)
	} else {
		if !proto.Equal(ef, TestCallerID) {
			f.t.Errorf("invalid effective caller id for %v: got %v expected %v", name, ef, TestCallerID)
		}
	}

	im := callerid.ImmediateCallerIDFromContext(ctx)
	if im == nil {
		f.t.Errorf("no immediate caller id for %v", name)
	} else {
		if !proto.Equal(im, TestVTGateCallerID) {
			f.t.Errorf("invalid immediate caller id for %v: got %v expected %v", name, im, TestVTGateCallerID)
		}
	}
}

// BeginTransactionID is a test transaction id for Begin.
const BeginTransactionID int64 = 9990

// Begin is part of the queryservice.QueryService interface
func (f *FakeQueryService) Begin(ctx context.Context, target *querypb.Target, options *querypb.ExecuteOptions) (int64, error) {
	if f.HasBeginError {
		return 0, f.TabletError
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	f.checkTargetCallerID(ctx, "Begin", target)
	if !proto.Equal(options, TestExecuteOptions) {
		f.t.Errorf("invalid Execute.ExecuteOptions: got %v expected %v", options, TestExecuteOptions)
	}
	return BeginTransactionID, nil
}

// CommitTransactionID is a test transaction id for Commit.
const CommitTransactionID int64 = 999044

// Commit is part of the queryservice.QueryService interface
func (f *FakeQueryService) Commit(ctx context.Context, target *querypb.Target, transactionID int64) error {
	if f.HasError {
		return f.TabletError
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	f.checkTargetCallerID(ctx, "Commit", target)
	if transactionID != CommitTransactionID {
		f.t.Errorf("Commit: invalid TransactionId: got %v expected %v", transactionID, CommitTransactionID)
	}
	return nil
}

// RollbackTransactionID is a test transactin id for Rollback.
const RollbackTransactionID int64 = 999044

// Rollback is part of the queryservice.QueryService interface
func (f *FakeQueryService) Rollback(ctx context.Context, target *querypb.Target, transactionID int64) error {
	if f.HasError {
		return f.TabletError
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	f.checkTargetCallerID(ctx, "Rollback", target)
	if transactionID != RollbackTransactionID {
		f.t.Errorf("Rollback: invalid TransactionId: got %v expected %v", transactionID, RollbackTransactionID)
	}
	return nil
}

// Dtid is a test dtid
const Dtid string = "aa"

// Prepare is part of the queryservice.QueryService interface
func (f *FakeQueryService) Prepare(ctx context.Context, target *querypb.Target, transactionID int64, dtid string) (err error) {
	if f.HasError {
		return f.TabletError
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	f.checkTargetCallerID(ctx, "Prepare", target)
	if transactionID != CommitTransactionID {
		f.t.Errorf("Prepare: invalid TransactionID: got %v expected %v", transactionID, CommitTransactionID)
	}
	if dtid != Dtid {
		f.t.Errorf("Prepare: invalid dtid: got %s expected %s", dtid, Dtid)
	}
	return nil
}

// CommitPrepared is part of the queryservice.QueryService interface
func (f *FakeQueryService) CommitPrepared(ctx context.Context, target *querypb.Target, dtid string) (err error) {
	if f.HasError {
		return f.TabletError
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	f.checkTargetCallerID(ctx, "CommitPrepared", target)
	if dtid != Dtid {
		f.t.Errorf("CommitPrepared: invalid dtid: got %s expected %s", dtid, Dtid)
	}
	return nil
}

// RollbackPrepared is part of the queryservice.QueryService interface
func (f *FakeQueryService) RollbackPrepared(ctx context.Context, target *querypb.Target, dtid string, originalID int64) (err error) {
	if f.HasError {
		return f.TabletError
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	f.checkTargetCallerID(ctx, "RollbackPrepared", target)
	if originalID != RollbackTransactionID {
		f.t.Errorf("RollbackPrepared: invalid TransactionID: got %v expected %v", originalID, RollbackTransactionID)
	}
	if dtid != Dtid {
		f.t.Errorf("RollbackPrepared: invalid dtid: got %s expected %s", dtid, Dtid)
	}
	return nil
}

// Participants is a test list of 2pc participants.
var Participants = []*querypb.Target{{
	Keyspace: "ks0",
	Shard:    "0",
}, {
	Keyspace: "ks1",
	Shard:    "1",
}}

// TargetsEqual returns true if the targets are equal.
func TargetsEqual(t1, t2 []*querypb.Target) bool {
	if len(t1) != len(t2) {
		return false
	}
	for i, t := range t1 {
		if !proto.Equal(t, t2[i]) {
			return false
		}
	}
	return true
}

// CreateTransaction is part of the queryservice.QueryService interface
func (f *FakeQueryService) CreateTransaction(ctx context.Context, target *querypb.Target, dtid string, participants []*querypb.Target) (err error) {
	if f.HasError {
		return f.TabletError
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	f.checkTargetCallerID(ctx, "CreateTransaction", target)
	if dtid != Dtid {
		f.t.Errorf("CreateTransaction: invalid dtid: got %s expected %s", dtid, Dtid)
	}
	if !TargetsEqual(participants, Participants) {
		f.t.Errorf("invalid CreateTransaction participants: got %v, expected %v", participants, Participants)
	}
	return nil
}

// StartCommit is part of the queryservice.QueryService interface
func (f *FakeQueryService) StartCommit(ctx context.Context, target *querypb.Target, transactionID int64, dtid string) (err error) {
	if f.HasError {
		return f.TabletError
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	f.checkTargetCallerID(ctx, "StartCommit", target)
	if transactionID != CommitTransactionID {
		f.t.Errorf("StartCommit: invalid TransactionID: got %v expected %v", transactionID, CommitTransactionID)
	}
	if dtid != Dtid {
		f.t.Errorf("StartCommit: invalid dtid: got %s expected %s", dtid, Dtid)
	}
	return nil
}

// SetRollback is part of the queryservice.QueryService interface
func (f *FakeQueryService) SetRollback(ctx context.Context, target *querypb.Target, dtid string, transactionID int64) (err error) {
	if f.HasError {
		return f.TabletError
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	f.checkTargetCallerID(ctx, "SetRollback", target)
	if transactionID != CommitTransactionID {
		f.t.Errorf("SetRollback: invalid TransactionID: got %v expected %v", transactionID, CommitTransactionID)
	}
	if dtid != Dtid {
		f.t.Errorf("SetRollback: invalid dtid: got %s expected %s", dtid, Dtid)
	}
	return nil
}

// ConcludeTransaction is part of the queryservice.QueryService interface
func (f *FakeQueryService) ConcludeTransaction(ctx context.Context, target *querypb.Target, dtid string) (err error) {
	if f.HasError {
		return f.TabletError
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	f.checkTargetCallerID(ctx, "ConcludeTransaction", target)
	if dtid != Dtid {
		f.t.Errorf("ConcludeTransaction: invalid dtid: got %s expected %s", dtid, Dtid)
	}
	return nil
}

// Metadata is a test metadata for 2pc transactions.
var Metadata = &querypb.TransactionMetadata{
	Dtid:         "aa",
	State:        querypb.TransactionState_PREPARE,
	TimeCreated:  1,
	Participants: Participants,
}

// ReadTransaction is part of the queryservice.QueryService interface
func (f *FakeQueryService) ReadTransaction(ctx context.Context, target *querypb.Target, dtid string) (metadata *querypb.TransactionMetadata, err error) {
	if f.HasError {
		return nil, f.TabletError
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	f.checkTargetCallerID(ctx, "ReadTransaction", target)
	if dtid != Dtid {
		f.t.Errorf("ReadTransaction: invalid dtid: got %s expected %s", dtid, Dtid)
	}
	return Metadata, nil
}

// ExecuteQuery is a fake test query.
const ExecuteQuery = "executeQuery"

// ExecuteBindVars is a test bind var.
var ExecuteBindVars = map[string]*querypb.BindVariable{
	"bind1": sqltypes.Int64BindVariable(1114444),
}

// ExecuteTransactionID is a test transaction id.
const ExecuteTransactionID int64 = 678

// ExecuteQueryResult is a test query result.
var ExecuteQueryResult = sqltypes.Result{
	Fields: []*querypb.Field{
		{
			Name: "field1",
			Type: sqltypes.Int8,
		},
		{
			Name: "field2",
			Type: sqltypes.Char,
		},
	},
	RowsAffected: 123,
	InsertID:     72,
	Rows: [][]sqltypes.Value{
		{
			sqltypes.TestValue(sqltypes.Int8, "1"),
			sqltypes.NULL,
		},
		{
			sqltypes.TestValue(sqltypes.Int8, "2"),
			sqltypes.TestValue(sqltypes.Char, "row2 value2"),
		},
	},
	Extras: &querypb.ResultExtras{
		EventToken: &querypb.EventToken{
			Timestamp: 456321,
			Shard:     "test_shard",
			Position:  "test_position",
		},
		Fresher: true,
	},
}

// Execute is part of the queryservice.QueryService interface
func (f *FakeQueryService) Execute(ctx context.Context, target *querypb.Target, sql string, bindVariables map[string]*querypb.BindVariable, transactionID int64, options *querypb.ExecuteOptions) (*sqltypes.Result, error) {
	if f.HasError {
		return nil, f.TabletError
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	if sql != ExecuteQuery {
		f.t.Errorf("invalid Execute.Query.Sql: got %v expected %v", sql, ExecuteQuery)
	}
	if !sqltypes.BindVariablesEqual(bindVariables, ExecuteBindVars) {
		f.t.Errorf("invalid Execute.BindVariables: got %v expected %v", bindVariables, ExecuteBindVars)
	}
	if !proto.Equal(options, TestExecuteOptions) {
		f.t.Errorf("invalid Execute.ExecuteOptions: got %v expected %v", options, TestExecuteOptions)
	}
	f.checkTargetCallerID(ctx, "Execute", target)
	if transactionID != f.ExpectedTransactionID {
		f.t.Errorf("invalid Execute.TransactionId: got %v expected %v", transactionID, f.ExpectedTransactionID)
	}
	return &ExecuteQueryResult, nil
}

// StreamExecuteQuery is a fake test query for streaming.
const StreamExecuteQuery = "streamExecuteQuery"

// StreamExecuteBindVars is a test bind var for streaming.
var StreamExecuteBindVars = map[string]*querypb.BindVariable{
	"bind1": sqltypes.Int64BindVariable(93848000),
}

// StreamExecuteQueryResult1 is the first packet of a streaming result.
var StreamExecuteQueryResult1 = sqltypes.Result{
	Fields: []*querypb.Field{
		{
			Name: "field1",
			Type: sqltypes.Int8,
		},
		{
			Name: "field2",
			Type: sqltypes.Char,
		},
	},
}

// StreamExecuteQueryResult2 is the second packet of a streaming result.
var StreamExecuteQueryResult2 = sqltypes.Result{
	Rows: [][]sqltypes.Value{
		{
			sqltypes.TestValue(sqltypes.Int8, "1"),
			sqltypes.TestValue(sqltypes.Char, "row1 value2"),
		},
		{
			sqltypes.TestValue(sqltypes.Int8, "2"),
			sqltypes.TestValue(sqltypes.Char, "row2 value2"),
		},
	},
}

// StreamExecute is part of the queryservice.QueryService interface
func (f *FakeQueryService) StreamExecute(ctx context.Context, target *querypb.Target, sql string, bindVariables map[string]*querypb.BindVariable, options *querypb.ExecuteOptions, callback func(*sqltypes.Result) error) error {
	if f.Panics && f.StreamExecutePanicsEarly {
		panic(fmt.Errorf("test-triggered panic early"))
	}
	if sql != StreamExecuteQuery {
		f.t.Errorf("invalid StreamExecute.Sql: got %v expected %v", sql, StreamExecuteQuery)
	}
	if !sqltypes.BindVariablesEqual(bindVariables, StreamExecuteBindVars) {
		f.t.Errorf("invalid StreamExecute.BindVariables: got %v expected %v", bindVariables, StreamExecuteBindVars)
	}
	if !proto.Equal(options, TestExecuteOptions) {
		f.t.Errorf("invalid StreamExecute.ExecuteOptions: got %v expected %v", options, TestExecuteOptions)
	}
	f.checkTargetCallerID(ctx, "StreamExecute", target)
	if err := callback(&StreamExecuteQueryResult1); err != nil {
		f.t.Errorf("callback1 failed: %v", err)
	}
	if f.Panics && !f.StreamExecutePanicsEarly {
		// wait until the client gets the response, then panics
		<-f.PanicWait
		panic(fmt.Errorf("test-triggered panic late"))
	}
	if f.HasError {
		// wait until the client has the response, since all
		// streaming implementation may not send previous
		// messages if an error has been triggered.
		<-f.ErrorWait
		return f.TabletError
	}
	if err := callback(&StreamExecuteQueryResult2); err != nil {
		f.t.Errorf("callback2 failed: %v", err)
	}
	return nil
}

// ExecuteBatchQueries are test queries for batch.
var ExecuteBatchQueries = []*querypb.BoundQuery{
	{
		Sql: "executeBatchQueries1",
		BindVariables: map[string]*querypb.BindVariable{
			"bind1": sqltypes.Int64BindVariable(43),
		},
	},
	{
		Sql: "executeBatchQueries2",
		BindVariables: map[string]*querypb.BindVariable{
			"bind2": sqltypes.Int64BindVariable(72),
		},
	},
}

// ExecuteBatchTransactionID is a test transaction id for batch.
const ExecuteBatchTransactionID int64 = 678

// ExecuteBatchQueryResultList is a list of test query results.
var ExecuteBatchQueryResultList = []sqltypes.Result{
	{
		Fields: []*querypb.Field{
			{
				Name: "field1",
				Type: sqltypes.Int8,
			},
		},
		RowsAffected: 1232,
		InsertID:     712,
		Rows: [][]sqltypes.Value{
			{
				sqltypes.TestValue(sqltypes.Int8, "1"),
			},
			{
				sqltypes.TestValue(sqltypes.Int8, "2"),
			},
		},
		Extras: &querypb.ResultExtras{
			EventToken: &querypb.EventToken{
				Timestamp: 456322,
				Shard:     "test_shard2",
				Position:  "test_position2",
			},
			Fresher: true,
		},
	},
	{
		Fields: []*querypb.Field{
			{
				Name: "field1",
				Type: sqltypes.VarBinary,
			},
		},
		RowsAffected: 12333,
		InsertID:     74442,
		Rows: [][]sqltypes.Value{
			{
				sqltypes.NewVarBinary("row1 value1"),
			},
			{
				sqltypes.NewVarBinary("row1 value2"),
			},
		},
	},
}

// ExecuteBatch is part of the queryservice.QueryService interface
func (f *FakeQueryService) ExecuteBatch(ctx context.Context, target *querypb.Target, queries []*querypb.BoundQuery, asTransaction bool, transactionID int64, options *querypb.ExecuteOptions) ([]sqltypes.Result, error) {
	if f.HasError {
		return nil, f.TabletError
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	if !proto.Equal(
		&querypb.ExecuteBatchRequest{Queries: queries},
		&querypb.ExecuteBatchRequest{Queries: ExecuteBatchQueries},
	) {
		f.t.Errorf("invalid ExecuteBatch.Queries: got %v expected %v", queries, ExecuteBatchQueries)
	}
	if !proto.Equal(options, TestExecuteOptions) {
		f.t.Errorf("invalid ExecuteBatch.ExecuteOptions: got %v expected %v", options, TestExecuteOptions)
	}
	f.checkTargetCallerID(ctx, "ExecuteBatch", target)
	if asTransaction != TestAsTransaction {
		f.t.Errorf("invalid ExecuteBatch.AsTransaction: got %v expected %v", asTransaction, TestAsTransaction)
	}
	if transactionID != f.ExpectedTransactionID {
		f.t.Errorf("invalid ExecuteBatch.TransactionId: got %v expected %v", transactionID, f.ExpectedTransactionID)
	}
	return ExecuteBatchQueryResultList, nil
}

// SplitQuerySplitColumns is a test list for column splits.
var SplitQuerySplitColumns = []string{"nice_column_to_split"}

// SplitQuerySplitCount is a test split count.
const SplitQuerySplitCount = 372

// SplitQueryBoundQuery is a test query for splits.
var SplitQueryBoundQuery = &querypb.BoundQuery{
	Sql: "splitQuery",
	BindVariables: map[string]*querypb.BindVariable{
		"bind1": sqltypes.Int64BindVariable(43),
	},
}

// SplitQueryNumRowsPerQueryPart is a test num rows for split.
const SplitQueryNumRowsPerQueryPart = 123

// SplitQueryAlgorithm is a test algorithm for splits.
const SplitQueryAlgorithm = querypb.SplitQueryRequest_FULL_SCAN

// SplitQueryQuerySplitList is a test result for splits.
var SplitQueryQuerySplitList = []*querypb.QuerySplit{
	{
		Query: &querypb.BoundQuery{
			Sql: "splitQuery",
			BindVariables: map[string]*querypb.BindVariable{
				"bind1":       sqltypes.Int64BindVariable(43),
				"keyspace_id": sqltypes.Int64BindVariable(3333),
			},
		},
		RowCount: 4456,
	},
}

// BeginExecute combines Begin and Execute.
func (f *FakeQueryService) BeginExecute(ctx context.Context, target *querypb.Target, sql string, bindVariables map[string]*querypb.BindVariable, options *querypb.ExecuteOptions) (*sqltypes.Result, int64, error) {
	transactionID, err := f.Begin(ctx, target, options)
	if err != nil {
		return nil, 0, err
	}

	result, err := f.Execute(ctx, target, sql, bindVariables, transactionID, options)
	return result, transactionID, err
}

// BeginExecuteBatch combines Begin and ExecuteBatch.
func (f *FakeQueryService) BeginExecuteBatch(ctx context.Context, target *querypb.Target, queries []*querypb.BoundQuery, asTransaction bool, options *querypb.ExecuteOptions) ([]sqltypes.Result, int64, error) {
	transactionID, err := f.Begin(ctx, target, options)
	if err != nil {
		return nil, 0, err
	}

	results, err := f.ExecuteBatch(ctx, target, queries, asTransaction, transactionID, options)
	return results, transactionID, err
}

var (
	// MessageName is a test message name.
	MessageName = "vitess_message"

	// MessageStreamResult is a test stream result.
	MessageStreamResult = &sqltypes.Result{
		Fields: []*querypb.Field{{
			Name: "id",
			Type: sqltypes.VarBinary,
		}, {
			Name: "message",
			Type: sqltypes.VarBinary,
		}},
		Rows: [][]sqltypes.Value{{
			sqltypes.NewVarBinary("1"),
			sqltypes.NewVarBinary("row1 value2"),
		}, {
			sqltypes.NewVarBinary("2"),
			sqltypes.NewVarBinary("row2 value2"),
		}},
	}

	// MessageIDs is a test list of message ids.
	MessageIDs = []*querypb.Value{{
		Type:  sqltypes.VarChar,
		Value: []byte("1"),
	}}
)

// MessageStream is part of the queryservice.QueryService interface
func (f *FakeQueryService) MessageStream(ctx context.Context, target *querypb.Target, name string, callback func(*sqltypes.Result) error) (err error) {
	if f.HasError {
		return f.TabletError
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	if name != MessageName {
		f.t.Errorf("name: %s, want %s", name, MessageName)
	}
	callback(MessageStreamResult)
	return nil
}

// MessageAck is part of the queryservice.QueryService interface
func (f *FakeQueryService) MessageAck(ctx context.Context, target *querypb.Target, name string, ids []*querypb.Value) (count int64, err error) {
	if f.HasError {
		return 0, f.TabletError
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	if name != MessageName {
		f.t.Errorf("name: %s, want %s", name, MessageName)
	}
	if !sqltypes.Proto3ValuesEqual(ids, MessageIDs) {
		f.t.Errorf("ids: %v, want %v", ids, MessageIDs)
	}
	return 1, nil
}

// SplitQuery is part of the queryservice.QueryService interface
func (f *FakeQueryService) SplitQuery(
	ctx context.Context,
	target *querypb.Target,
	query *querypb.BoundQuery,
	splitColumns []string,
	splitCount int64,
	numRowsPerQueryPart int64,
	algorithm querypb.SplitQueryRequest_Algorithm,
) ([]*querypb.QuerySplit, error) {

	if f.HasError {
		return nil, f.TabletError
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	f.checkTargetCallerID(ctx, "SplitQuery", target)
	if !proto.Equal(query, SplitQueryBoundQuery) {
		f.t.Errorf("invalid SplitQuery.SplitQueryRequest.Query: got %v expected %v",
			query, SplitQueryBoundQuery)
	}
	if !reflect.DeepEqual(splitColumns, SplitQuerySplitColumns) {
		f.t.Errorf("invalid SplitQuery.SplitColumn: got %v expected %v",
			splitColumns, SplitQuerySplitColumns)
	}
	if splitCount != SplitQuerySplitCount {
		f.t.Errorf("invalid SplitQuery.SplitCount: got %v expected %v",
			splitCount, SplitQuerySplitCount)
	}
	if numRowsPerQueryPart != SplitQueryNumRowsPerQueryPart {
		f.t.Errorf("invalid SplitQuery.numRowsPerQueryPart: got %v expected %v",
			numRowsPerQueryPart, SplitQueryNumRowsPerQueryPart)
	}
	if algorithm != SplitQueryAlgorithm {
		f.t.Errorf("invalid SplitQuery.algorithm: got %v expected %v",
			algorithm, SplitQueryAlgorithm)
	}
	return SplitQueryQuerySplitList, nil
}

// TestStreamHealthStreamHealthResponse is a test stream health response.
var TestStreamHealthStreamHealthResponse = &querypb.StreamHealthResponse{
	Target: &querypb.Target{
		Keyspace:   "test_keyspace",
		Shard:      "test_shard",
		TabletType: topodatapb.TabletType_RDONLY,
	},
	Serving: true,
	TabletExternallyReparentedTimestamp: 1234589,
	RealtimeStats: &querypb.RealtimeStats{
		HealthError:                            "random error",
		SecondsBehindMaster:                    234,
		BinlogPlayersCount:                     1,
		SecondsBehindMasterFilteredReplication: 2,
		CpuUsage: 1.0,
	},
}

// TestStreamHealthErrorMsg is a test error message for health streaming.
var TestStreamHealthErrorMsg = "to trigger a server error"

// StreamHealth is part of the queryservice.QueryService interface
func (f *FakeQueryService) StreamHealth(ctx context.Context, callback func(*querypb.StreamHealthResponse) error) error {
	if f.HasError {
		return errors.New(TestStreamHealthErrorMsg)
	}
	if f.Panics {
		panic(fmt.Errorf("test-triggered panic"))
	}
	shr := f.StreamHealthResponse
	if shr == nil {
		shr = TestStreamHealthStreamHealthResponse
	}
	callback(shr)
	return nil
}

// UpdateStreamPosition is a test update stream position.
const UpdateStreamPosition = "update stream position"

// UpdateStreamTimestamp is a test update stream timestamp.
const UpdateStreamTimestamp = 123654

// UpdateStreamStreamEvent1 is a test update stream event.
var UpdateStreamStreamEvent1 = querypb.StreamEvent{
	Statements: []*querypb.StreamEvent_Statement{
		{
			Category:  querypb.StreamEvent_Statement_DML,
			TableName: "table1",
		},
	},
	EventToken: &querypb.EventToken{
		Timestamp: 789654,
		Shard:     "shard1",
		Position:  "streaming position 1",
	},
}

// UpdateStreamStreamEvent2 is a test update stream event.
var UpdateStreamStreamEvent2 = querypb.StreamEvent{
	Statements: []*querypb.StreamEvent_Statement{
		{
			Category:  querypb.StreamEvent_Statement_DML,
			TableName: "table2",
		},
	},
	EventToken: &querypb.EventToken{
		Timestamp: 789655,
		Shard:     "shard1",
		Position:  "streaming position 2",
	},
}

// UpdateStream is part of the queryservice.QueryService interface
func (f *FakeQueryService) UpdateStream(ctx context.Context, target *querypb.Target, position string, timestamp int64, callback func(*querypb.StreamEvent) error) error {
	if f.Panics && f.UpdateStreamPanicsEarly {
		panic(fmt.Errorf("test-triggered panic early"))
	}
	if position != UpdateStreamPosition {
		f.t.Errorf("invalid UpdateStream.position: got %v expected %v", position, UpdateStreamPosition)
	}
	if timestamp != UpdateStreamTimestamp {
		f.t.Errorf("invalid UpdateStream.timestamp: got %v expected %v", timestamp, UpdateStreamTimestamp)
	}
	f.checkTargetCallerID(ctx, "UpdateStream", target)
	if err := callback(&UpdateStreamStreamEvent1); err != nil {
		f.t.Errorf("callback1 failed: %v", err)
	}
	if f.Panics && !f.UpdateStreamPanicsEarly {
		// wait until the client gets the response, then panics
		<-f.PanicWait
		panic(fmt.Errorf("test-triggered panic late"))
	}
	if f.HasError {
		// wait until the client has the response, since all
		// streaming implementation may not send previous
		// messages if an error has been triggered.
		<-f.ErrorWait
		return f.TabletError
	}
	if err := callback(&UpdateStreamStreamEvent2); err != nil {
		f.t.Errorf("callback2 failed: %v", err)
	}
	return nil
}

// CreateFakeServer returns the fake server for the tests
func CreateFakeServer(t *testing.T) *FakeQueryService {
	return &FakeQueryService{
		t: t,
	}
}