Compare per-order and batched lookups against a small order fixture. Check record equality and missing relationships separately before accepting the change.
Read the order list, then retrieve a customer and its lines for each order.
Read orders once, retrieve unique customer IDs together, then retrieve lines for the full order set.
The browser executes instrumented repository lookups on these synthetic records. Use the acceptance pattern to agree the SQL trace and response checks for your Rails application.
No calls recorded.
Both modes can agree while the same customer is absent. Completeness remains a separate receiving condition.