Merge branch 'test/#691-failing-test-for-#685' into hotfix/#685-DBAL-997-undefined-_conn-property

Close #691

tests/Doctrine/Tests/DBAL/ConnectionTest.php

@@ -403,6 +403,13 @@ SQLSTATE[HY000]: General error: 1 near \"MUUHAAAAHAAAA\"");
         $this->assertSame($result, $conn->fetchColumn($statement, $params, $column, $types));
     }
 
+    public function testConnectionIsClosed()
+    {
+        $this->setExpectedException('Doctrine\\DBAL\\Exception\\DriverException');
+        $this->_conn->close();
+        $this->_conn->quoteIdentifier('Bug');
+    }
+
     public function testFetchAll()
     {
         $statement = 'SELECT * FROM foo WHERE bar = ?';