Klaus

Eureka

 Fri, 19 Jan 2018 00:13:59 +0100 
- $dsn = $this->driver_dbtype . ':host=' . $server . (intval($port) ? '' : ';port=' . $port);
+ $dsn = $this->driver_dbtype . ':host=' . $server . (intval($port) ? ';port=' . $port : '');

It took me three evenings to find out why some database unit tests just did not want to work. :facepalm