RuleId/PolicyId/PolicySetId uniqueness enforcement
Enforce uniqueness of ruleId/policyId/PolicySet, only what's necessary and reasonable to differentiate in the logs :
RuleId should be unique within a policy: https://lists.oasis-open.org/archives/xacml/201310/msg00025.html As a result, in the logs, we should identify a rule element by: Policy[XX]/Rule[YY]
PolicyId (resp. PolicySetId) should be unique across all policies loaded by PDP so that PolicyIdReferences (resp. PolicySetIdReferences) in Responses' PolicyIdentifierList are absolute references to applicable policies (no ambiguity).
Provide unit tests for all use cases.