add functional driver test case for connecting without dbname parameter

tests/Doctrine/Tests/DBAL/Functional/Driver/AbstractDriverTest.php

+<?php
+
+namespace Doctrine\Tests\DBAL\Functional\Driver;
+
+use Doctrine\DBAL\Connection;
+use Doctrine\Tests\DbalFunctionalTestCase;
+
+abstract class AbstractDriverTest extends DbalFunctionalTestCase
+{
+    /**
+     * The driver instance under test.
+     *
+     * @var \Doctrine\DBAL\Driver
+     */
+    private $driver;
+
+    protected function setUp()
+    {
+        parent::setUp();
+
+        $this->driver = $this->createDriver();
+    }
+
+    /**
+     * @group DBAL-1215
+     */
+    public function testConnectsWithoutDatabaseNameParameter()
+    {
+        $params = $this->_conn->getParams();
+        unset($params['dbname']);
+
+        $user = isset($params['user']) ? $params['user'] : null;
+        $password = isset($params['password']) ? $params['password'] : null;
+
+        $connection = $this->driver->connect($params, $user, $password);
+
+        $this->assertInstanceOf('Doctrine\DBAL\Driver\Connection', $connection);
+    }
+
+    /**
+     * @group DBAL-1215
+     */
+    public function testReturnsDatabaseNameWithoutDatabaseNameParameter()
+    {
+        $params = $this->_conn->getParams();
+        unset($params['dbname']);
+
+        $connection = new Connection(
+            $params,
+            $this->_conn->getDriver(),
+            $this->_conn->getConfiguration(),
+            $this->_conn->getEventManager()
+        );
+
+        $this->assertSame(
+            $this->getDatabaseNameForConnectionWithoutDatabaseNameParameter(),
+            $this->driver->getDatabase($connection)
+        );
+    }
+
+    /**
+     * @return \Doctrine\DBAL\Driver
+     */
+    abstract protected function createDriver();
+
+    /**
+     * @return string|null
+     */
+    protected function getDatabaseNameForConnectionWithoutDatabaseNameParameter()
+    {
+        return null;
+    }
+}

tests/Doctrine/Tests/DBAL/Functional/Driver/PDOPgSql/DriverTest.php

+<?php
+
+namespace Doctrine\Tests\DBAL\Functional\Driver\PDOPgSql;
+
+use Doctrine\DBAL\Driver\PDOPgSql\Driver;
+use Doctrine\Tests\DBAL\Functional\Driver\AbstractDriverTest;
+
+class DriverTest extends AbstractDriverTest
+{
+    protected function setUp()
+    {
+        if (! extension_loaded('pdo_pgsql')) {
+            $this->markTestSkipped('pdo_pgsql is not installed.');
+        }
+
+        parent::setUp();
+
+        if (! $this->_conn->getDriver() instanceof Driver) {
+            $this->markTestSkipped('pdo_pgsql only test.');
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function createDriver()
+    {
+        return new Driver();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function getDatabaseNameForConnectionWithoutDatabaseNameParameter()
+    {
+        return 'template1';
+    }
+}