A compatibility engine can be deterministic and still be dishonest. The obvious failure is a wrong calculation. The subtler failure is unjustified certainty: turning a blank birth time into noon, allowing a nickname to change a result, or comparing an Hour Branch that was never calculated.
This tutorial describes a test strategy for a two-chart pipeline. The domain example is BaZi, a traditional symbolic framework for reflection. It is not scientifically validated as a prediction method. The fixture below is fictional software test data, not a customer story. Its public evidence repository is brand-owned by Bazi Clarity, so it is implementation evidence—not independent validation or social proof.
The engineering goal is narrow: given two input records, preserve what is known, expose what is unknown, and make every comparison reproducible.
Define the integrity contract before the formula
Start with invariants, not an attractive compatibility percentage. A useful contract for this pipeline is:
