Regression testing

What is regression testing after an accounting-software update?

⚠ Machine-translated answer, not yet manually reviewed. For the exact wording, see the Slovak original.

Short answer

Regression testing means repeating the relevant tests after an ERP or accounting-software update to confirm that generating, validating, sending and receiving e-invoice XML still works and that the update introduced no unintended changes. It is a recommended operational control, not a statutory obligation under Slovak VAT or accounting law.

After each updatecii

Recommended step

Verify functionality e-invoice after changing the software version.

Both normal and atypical scenarios

Scope of testing

Credit, foreign currency, multiple attachments and so on.

Validator Peppol Testbed

Verification tool

Checking the marketing rules before production.

Operating experience

No legal obligation

The company sets up this procedure itself in the internal control.

Detailed explanation

The reason for the need for regression testing is the risk that even a minor software update may unintentionally alter the way XML is generated – for example, the date format, rounding of amounts or field mapping – which could result in newly generated invoices failing validation or containing factually incorrect data. The recommended procedure is, following every major software update, to generate several test invoices covering both common and atypical scenarios (for example, a credit note, an invoice in a foreign currency, or an invoice with multiple attachments) and verify them using the Peppol Testbed validator before the updated system is put into use for actual business transactions.

As set out in the Act

Regression testing is not specifically regulated by Act No. 222/2004 Coll. on VAT or Act No. 431/2002 Coll. on Accounting. It relates to the taxpayer’s general responsibility for the accuracy and verifiability of issued invoices under Section 74 of the VAT Act.

Practical examples

  • After updating the ERP to a new version, the company generates a test invoice with a credit note and verifies it using a validator.
  • Regression testing reveals that the update has changed the format of the due date from what was expected.
  • The company will incorporate e-invoice regression testing as a standard step for every major software release.

Most common mistakes

  • “Regression testing following a software update is required by the VAT Act.” This is a recommended operational practice, not a legal obligation.
  • “It is sufficient to test just one standard invoice after the update.” It is recommended to cover atypical scenarios as well, such as a credit note or an invoice with attachments.
  • “A software update cannot affect the accuracy of the generated XML.” Even a minor change may unintentionally affect the formatting or field mapping in the resulting XML.

Conclusion

Repeat the essential e-invoice tests after material software changes; this is good operational practice rather than a separate statutory duty.

Legal basis

  • Act No. 222/2004 Coll. on VAT, Section 74

Related questions

This is not legal advice. Sources: Act No. 222/2004 Coll. on VAT, EN 16931 and Peppol BIS Billing 3.0 (OpenPeppol documentation, docs.peppol.eu), official methodological and information materials from the Slovak Financial Administration on e-invoices. Verified on 7 July 2026.