Staying OO and Testable while working with a database
- by Adam Backstrom
What are some OOP strategies for working with a database but keeping thing testable? Say I have a User class and my production environment works against MySQL. I see a couple possible approaches, shown here using PHP:
Pass in a $data_source with interfaces for load() and save(), to abstract the backend source of data. When testing, pass a different data store.
$user = new User( $mysql_data_source );
$user-load( 'bob' );
$user-setNickname( 'Robby' );
$user-save();
Use a factory that accesses the database and passes the result row to User's constructor. When testing, manually generate the $row parameter, or mock the object in UserFactory::$data_source. (How might I save changes to the record?)
class UserFactory {
static $data_source;
public static function fetch( $username ) {
$row = self::$data_source->get( [params] );
$user = new User( $row );
return $user;
}
}
I have Design Patterns and Clean Code here next to me, but I'm struggling to find applicable concepts.
