These are test documents for Simpler invoicing, to use with a validation package.
Generally, the tests are placed in a directory with the name of the SI-UBL version they are meant to test. There are a few tests in the general/ directory that are for any version.
The filenames have the form SI-UBL-\<version>-\<status>-\<rule> where:
For instance, the test file SI-UBL-1.1/SI-UBL1.1-error-BII2-T10-R044.xml is a test that violates BII2-T10-R044 from the peppol validation artefacts within SI-UBL 1.1. SI-UBL-1.0/SI-UBL1.0-ok-minimal.xml is a minimal document that should validate under the rules of SI-UBL 1.0.
If you find any faults in these documents, please contact SimplerInvoicing.