On the SitePoint PHP blog author Andrew Carter has shared a "quick tip" about using a disposable database in the testing of your Symfony-based applications.

Testing code that interacts with a database can be a massive pain. Some developers mock database abstractions, and thus do not test the actual query. Others create a test database for the development environment, but this can also be a pain when it comes to continuous integration and maintaining the state of this database.

In-memory databases are an alternative to these options. As they exist only in the memory of the application, they are truly disposable and great for testing. Thankfully, these are very easy to set up with Symfony applications that use Doctrine.

He talks first about the built-in functionality Symfony has to use different configuration files for different environments. This allows for easier testing in a more isolated setup than replicating development. He then shows how to use Doctrine with a SQLite in-memory database with a simple update to the config_test YAML configuration file. He also includes the code for a DatabasePrimer class that gets the Doctrine entity manager and executes the the schema tool to set up the schema in the database and "prime" it with any fixtures you might need.