},
	}

	defer func() {
		if !reflect.DeepEqual(conn.got, conn.expect) {
			t.Errorf("expect %#v but got %#v", conn.expect, conn.got)
		}
	}()

	db, err := gorm.Open(mysql.New(mysql.Config{Conn: conn, DisableWithReturning: true}))
	if err != nil {
		t.Fatalf("Should open db success, but got %v", err)
	}

	tx := db.Begin()

			tx.Create(&user)

			var result User
			tx.First(&result)
			wg.Done()
		}()
	}
	wg.Wait()

	conn, ok := tx.ConnPool.(*gorm.PreparedStmtDB)
	AssertEqual(t, ok, true)
	AssertEqual(t, len(conn.Stmts), 2)
	for _, stmt := range conn.Stmts {
		if stmt == nil {
			t.Fatalf("stmt cannot bee nil")
		}
	}

	AssertEqual(t, sqlDB.Stats().InUse, 0)
}

	// Reason why cannot lock conn.PrepareContext
	// suppose the maxopen is 1, g1 is creating record and g2 is querying record.
	// 1. g1 begin tx, g1 is requeue because of waiting for the system call, now `db.ConnPool` db.numOpen == 1.
	// 2. g2 select lock `conn.PrepareContext(ctx, query)`, now db.numOpen == db.maxOpen , wait for release.
	// 3. g1 tx exec insert, wait for unlock `conn.PrepareContext(ctx, query)` to finish tx and release.

		return nil
	}); err == nil {
		t.Errorf("should returns error when commit with closed conn, got error %v", err)
	}

	if err := DB.Session(&gorm.Session{PrepareStmt: true}).Transaction(func(tx *gorm.DB) error {
		return nil
	}); err == nil {
		t.Errorf("should returns error when commit with closed conn, got error %v", err)
	}
}

func TestTransactionWithHooks(t *testing.T) {

	RollbackTo(tx *DB, name string) error
}

// TxBeginner tx beginner
type TxBeginner interface {
	BeginTx(ctx context.Context, opts *sql.TxOptions) (*sql.Tx, error)
}

// ConnPoolBeginner conn pool beginner
type ConnPoolBeginner interface {
	BeginTx(ctx context.Context, opts *sql.TxOptions) (ConnPool, error)
}

// TxCommitter tx committer
type TxCommitter interface {
	Commit() error
	Rollback() error

	if db.Error != nil {
		return db.Error
	}

	tx := db.getInstance()
	sqlDB, err := tx.DB()
	if err != nil {
		return
	}

	conn, err := sqlDB.Conn(tx.Statement.Context)
	if err != nil {
		return
	}

	defer conn.Close()
	tx.Statement.ConnPool = conn
	return fc(tx)
}

// Transaction start a transaction as a block, return error will rollback, otherwise to commit. Transaction executes an

	CreateBatchSize int
	// TranslateError enabling error translation
	TranslateError bool

	// ClauseBuilders clause builder
	ClauseBuilders map[string]clause.ClauseBuilder
	// ConnPool db conn pool
	ConnPool ConnPool
	// Dialector database dialector
	Dialector
	// Plugins registered plugins
	Plugins map[string]Plugin

	callbacks  *callbacks
	cacheStore *sync.Map
}