doctrine2/tests/lib/Doctrine_DbalTestCase.php

<?php
/**
 * Base testcase class for all dbal testcases.
 */
class Doctrine_DbalTestCase extends Doctrine_TestCase
{
    /**
     * setUp()
     *
     * Note: This setUp() and the one of OrmTestCase currently look identical. However,
     * please dont pull this method up. In the future with a separation of Dbal/Orm
     * this setUp() will take care of a DBAL connection and the ORM setUp() will take care
     * of an ORM connection/session/manager.
     */
    protected function setUp()
    {
        // Setup a db connection if there is none, yet. This makes it possible
        // to run tests that use a connection standalone.
        if ( ! isset($this->sharedFixture['connection'])) {
            $this->sharedFixture['connection'] = Doctrine_TestUtil::getConnection();
        }
    }
}