public function getErrorsForField(EntityDescriptor $ed, $field) {
		$r = array();
		foreach( static::$testedValues as $value ) {
			try {
				$ed->validateFieldValue($field, $value);
			} catch( InvalidFieldException $e ) {
				$r[$e->getKey()] = $e;
			}
		}
		return $r;
	}