There is something seems to be a bug.
For rule that contains additional check(e.g. METHOD:) alongside with URL match clicking "Test..." shows error message "Sorry, the TEST command can only be used with Rules that evaluate the URL.
Maybe it's because it's possible to edit matching pattern right in the "Test" popup(so it would need aditionally to parse rule string, take URL matching separately from other flags, allow it to be edited and finally to join all that again).
But currently it requires additional efforts to check such kind of rules:
1. Cut all the flags except REGEX:/EXCEPT:/<partial URL matching string>
2. Test it, modify if needed
3. Return all the flags back
4. Save the rule