Testing database connections

Hello, I'm still learning CodeIgniter so please forgive me if my question is ridiculous. In a previous version of CI, I would set the 'autoinit' variable in the database config file to false, and initialize my database in an if statement which would return true or false if the connection couldn't be made without throwing any warnings. If false I would load a page giving instructions on how to set the database config file. I'm not seeing a choice for autoinit in CI 3, so I assume I need to find another solution. Could anyone point me in the right direction? Thanks!