Car rental API integration testing
A practical implementation guide for rental businesses and technology teams preparing a supported Hannk deployment.
Agree the contract before writing integration code
Confirm the current Hannk documentation, available environment and scope with the onboarding team. Agree the identifiers, supported actions, data fields and authentication requirements. Public marketing pages explain capabilities; they are not an endpoint or payload reference.
Document which system owns each booking, driver approval, vehicle assignment and access period. Define how conflicts are resolved so two systems do not independently approve incompatible rental states.
Test the rental lifecycle
Create test cases for confirmation, driver approval, vehicle assignment, access issuance, collection, extension, return and closure. Check that each action relates to the intended customer and vehicle through the agreed identifiers.
Include cancellation before collection, an additional driver and a vehicle substitution. Verify that old permissions are handled as required and that a new vehicle is not accessible before its required approval steps are complete.
Test uncertainty and retries
Test network timeouts, unavailable services, delayed observations and incomplete responses. A request timing out does not necessarily mean the action failed. Use the documented state-confirmation and retry behaviour rather than guessing.
Where events or webhooks are supported, test duplicates and out-of-order delivery. Confirm the agreed authentication and validation method. Keep a record of processed events and prevent a repeated message from creating an unintended second action.
Test permissions and sensitive data
Check that customer and staff roles can perform only their authorised actions. Keep privileged secrets out of client applications, source repositories and logs. Use credentials assigned to the relevant integration and revoke them when access ends.
Test rejected credentials and unauthorised access without using real customer information. Confirm the lawful data flows, processing responsibilities and retention requirements. Production readiness includes data protection and access control, not only successful API requests.
Test vehicle data and command outcomes
Confirm available signals for the pilot vehicles and preserve their units and observation times. Test missing data, a stopped feed and a vehicle reassigned to another booking. A last-known location should not appear to staff as a guaranteed live position.
For supported vehicle commands, distinguish request submission, acknowledgement and the confirmed outcome using the agreed interface. Include failed access and customer recovery cases. Do not infer that a door opened solely from a submitted request.
Agree production release and recovery
Record test results, unresolved limitations and the person responsible for each operational exception. Decide how staff recognise a failed integration and what customer assistance remains available. Use a controlled pilot and retain a rollback or recovery plan.
Review integrations when either platform changes. Confirm version compatibility, supported notices and any applicable service commitments through the agreed documentation. This guide supplies a testing framework and deliberately does not invent Hannk endpoint names or schemas.