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: wrap_test.go
    path of file: ./repos/heketi/pkg/db
    
    the code of the file until where you have to start completion: //
// Copyright (c) 2018 The heketi Authors
//
// This file is licensed to you under your choice of the GNU Lesser
// General Public License, version 3 or any later version (LGPLv3 or
// later), or the GNU General Public License, version 2 (GPLv2), in all
// cases as published by the Free Software Foundation.
//

package db

import (
	"os"
	"testing"
	"time"

	"github.com/boltdb/bolt"
	"github.com/heketi/tests"
)

func Test
    
func TestTxWrapFailUpdateOnRO(t *testing.T) {
	tmpfile := tests.Tempfile()
	defer os.Remove(tmpfile)

	// Create a db
	db, err := bolt.Open(tmpfile, 0600, &bolt.Options{Timeout: 3 * time.Second})
	tests.Assert(t, err == nil, "expected (bolt.Open) err == nil, got:", err)
	tests.Assert(t, db != nil, "expected (bolt.Open) db != nil, got:", err)

	stuff := 0
	// f mimics a standalone function that wants a DB object but we want
	// to use it within an existing transaction
	f := func(db DB) error {
		stuff++
		db.Update(func(tx *bolt.Tx) error {
			stuff++
			return nil
		})
		stuff++
		return nil
	}

	defer func() {
		e := recover()
		tests.Assert(t, e != nil, "expected e != nil, got", e)
		tests.Assert(t, stuff == 2, "expected stuff == 2, got:", stuff)
	}()

	// generally you would want to correctly use DB or RODB so that the type
	// system can catch errors. However we have extra runtime guards against
	// calling a write method on a R/O TxWrap.
	db.Update(func(tx *bolt.Tx) error {
		stuff++
		f(WrapTxReadOnly(tx))
		stuff++
		return nil
	})

	t.Fatalf("should not reach this line")
}