On the subject of unit testing, the BaseX built-in unit module was used extensively during development. The tests for evaluation were written first, in support of that module, but this meant that the compile tests did not need to be written from scratch and could be adopted with little adjustment.

The Schematron conformance suite^[44] is a set of XML documents containing instances and schemas and their expected behaviour under a conformant implementation. An XQuery tool was written to generate unit tests from these assets.