SQL Server 2008 backup script I have a lot of SharePoint 2013 databases to backup and if update fail to  restore, so I want to automate this operations. 

ALTER DATABASE [TEST_1] SET OFFLINE WITH ROLLBACK IMMEDIATE
GO

BACKUP DATABASE [TEST_1] 
TO DISK = 'C:\path\test_1.bak' WITH NOINIT, STATS = 10
GO

ALTER DATABASE [TEST_1] SET ONLINE WITH ROLLBACK IMMEDIATE


But there is and error msg:


  Msg 942, Level 14, State 4, Line 1
  Database 'TEST_1' cannot be opened because it is offline. 
  
  Msg 3013, Level 16, State 1, Line 1
  BACKUP DATABASE is terminating abnormally.


Is it possbile to switch database offline, make backup and turn it in online mode after this?
It is not possible, because you cannot create a backup of an offline database.

From MSDN:


  Without the NO_TRUNCATE option, the database must be in the ONLINE
  state. If the database is in the SUSPENDED state, you might be able to
  create a backup by specifying NO_TRUNCATE. But if the database is in
  the OFFLINE or EMERGENCY state, BACKUP is not allowed even with
  NO_TRUNCATE