You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: index_merge_reader_test.go
    path of file: ./repos/tidb/pkg/executor/test/indexmergereadtest
    
    the code of the file until where you have to start completion: // Copyright 2019 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,
// 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 indexmergereadtest

import (
	"cmp"
	"context"
	"fmt"
	"math/rand"
	"regexp"
	"slices"
	"strconv"
	"strings"
	"sync"
	"testing"
	"time"

	"github.com/pingcap/failpoint"
	"github.com/pingcap/tidb/pkg/executor"
	"github.com/pingcap/tidb/pkg/session"
	"github.com/pingcap/tidb/pkg/testkit"
	"github.com/pingcap/tidb/pkg/util"
	"github.com/stretchr/testify/require"
)

func TestIndexMergePickAndExecTaskPani
    
func TestPartitionTableRandomIndexMerge(t *testing.T) {
	store := testkit.CreateMockStore(t)
	tk := testkit.NewTestKit(t, store)
	tk.MustExec("use test")
	tk.MustExec("set @@tidb_enable_index_merge=1")
	tk.MustExec("set @@tidb_partition_prune_mode='dynamic'")
	tk.MustExec(`create table t (a int, b int, key(a), key(b))
		partition by range (a) (
		partition p1 values less than (10),
		partition p2 values less than (20),
		partition p3 values less than (30),
		partition p4 values less than (40))`)
	tk.MustExec(`create table tnormal (a int, b int, key(a), key(b))`)

	values := make([]string, 0, 32)
	for i := 0; i < 32; i++ {
		values = append(values, fmt.Sprintf("(%v, %v)", rand.Intn(10), rand.Intn(10)))
	}
	tk.MustExec(fmt.Sprintf("insert into t values %v", strings.Join(values, ", ")))
	tk.MustExec(fmt.Sprintf("insert into tnormal values %v", strings.Join(values, ", ")))

	randRange := func() (int, int) {
		a, b := rand.Intn(10), rand.Intn(10)
		if a > b {
			return b, a
		}
		return a, b
	}
	for i := 0; i < 32; i++ {
		la, ra := randRange()
		lb, rb := randRange()
		cond := fmt.Sprintf("(a between %v and %v) or (b between %v and %v)", la, ra, lb, rb)
		result := tk.MustQuery("select * from tnormal where " + cond).Sort().Rows()
		tk.MustQuery("select /*+ USE_INDEX_MERGE(t, a, b) */ * from t where " + cond).Sort().Check(result)
	}
}