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// Copyright 2018 PingCAP, 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 agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
package memo
import (
"encoding/binary"
"reflect"
. "github.com/pingcap/check"
"github.com/pingcap/tidb/expression"
plannercore "github.com/pingcap/tidb/planner/core"
)
func (s *testMemoSuite) TestNewGroupExpr(c *C) {
p := &plannercore.LogicalLimit{}
expr := NewGroupExpr(p)
c.Assert(expr.ExprNode, Equals, p)
c.Assert(expr.Children, IsNil)
c.Assert(expr.Explored(0), IsFalse)
}
func (s *testMemoSuite) TestGroupExprFingerprint(c *C) {
p := &plannercore.LogicalLimit{Count: 3}
expr := NewGroupExpr(p)
childGroup := NewGroupWithSchema(nil, expression.NewSchema())
expr.SetChildren(childGroup)
// ChildNum(2 bytes) + ChildPointer(8 bytes) + LogicalLimit HashCode
planHash := p.HashCode()
buffer := make([]byte, 10+len(planHash))
binary.BigEndian.PutUint16(buffer, 1)
binary.BigEndian.PutUint64(buffer[2:], uint64(reflect.ValueOf(childGroup).Pointer()))
copy(buffer[10:], planHash)
c.Assert(expr.FingerPrint(), Equals, string(buffer))
}