Whenever getFakeTemplate() is called, it creates a FakeTemplate object (subclass of QuickTemplate) without a config object. QuickTemplate complains:
if ( $config === null ) {
wfDebug( __METHOD__ . ' was called with no Config instance passed to it' );
$config = MediaWikiServices::getInstance()->getMainConfig();
}This looks like it just wants a config object, hopefully the right one. For a FakeTemplate, this is probably fine, but the FakeTemplate should pass in the config object to quiet this thing down.