Production issues in e-invoicing often come from scenarios that were never exercised before launch. A useful test plan should go beyond happy-path sending and cover how the whole document flow behaves under realistic conditions.

What to include in testing

A strong test set usually covers:

  • valid invoices
  • invalid data and failed validation
  • missing references
  • attachment handling
  • support and retry workflows

This helps teams evaluate not just whether the integration works, but whether the product is ready for production support.

What teams often skip

Common gaps include:

  • unclear ownership during failed tests
  • no review of customer-facing error messages
  • no checks for downstream operational visibility

Those gaps become expensive after go-live because they turn simple issues into support escalations.

The practical goal

Testing should prove three things:

  1. documents can move correctly
  2. failures are understandable
  3. support can resolve problems without engineering involvement in every case

For rollout preparation, read How supplier onboarding for Peppol actually works and How to plan a Peppol rollout without creating ops debt .