Currently the Shopping portlet can be integrated with PayPal. One can test transactions via the paypal sandbox environment which uses the end address "sandbox.paypal.com." However, the liferay core code currently has the PayPalNoticiationAction URL hardcoded as:
URL url = new URL("https://www.paypal.com/cgi-bin/webscr");
If one desired to test transactions via Liferay, there currently is not a feature to determine which Paypal url to use for testing or for going live since there is only one hardcoded URL for paypal. This can be inconvenient as one is not able to distinguish test transaction versus live transactions.
It would be great if there was a portal property or feature that would allow users to specify which PayPal Url can be used for testing and which PayPal URL can be used for going live.