yii2-bootstrap/tests/unit/DatabaseTestCase.php

<?php

namespace yiiunit;

class DatabaseTestCase extends TestCase
{
    protected $database;
    protected $driverName = 'mysql';
    protected $db;

    protected function setUp()
    {
        $databases = $this->getParam('databases');
        $this->database = $databases[$this->driverName];
        $pdo_database = 'pdo_'.$this->driverName;

        if (!extension_loaded('pdo') || !extension_loaded($pdo_database)) {
            $this->markTestSkipped('pdo and pdo_'.$pdo_database.' extension are required.');
        }
    }

    /**
     * @param bool $reset whether to clean up the test database
     * @param bool $open whether to open and populate test database
     * @return \yii\db\Connection
     */
    public function getConnection($reset = true, $open = true)
    {
        if (!$reset && $this->db) {
            return $this->db;
        }
        $db = new \yii\db\Connection;
        $db->dsn = $this->database['dsn'];
        if (isset($this->database['username'])) {
            $db->username = $this->database['username'];
            $db->password = $this->database['password'];
        }
        if ($open) {
            $db->open();
            $lines = explode(';', file_get_contents($this->database['fixture']));
            foreach ($lines as $line) {
                if (trim($line) !== '') {
                    $db->pdo->exec($line);
                }
            }
        }
        $this->db = $db;
        return $db;
    }
}