Unit tests validate small components in isolation, while integration tests validate how those components work together in realistic workflows.
Decimal preserves predictable precision for monetary calculations and avoids floating-point rounding problems.
They make failures easier to diagnose because the reason for the expected behavior is written directly in the test.
Markers made it easy to run only unit tests or only integration tests depending on the feedback needed.
Fixtures reduced duplication and provided consistent setup data for multiple tests.
They confirmed that validation, stock reduction, order recording, and totals worked together as a complete workflow.
Coverage highlights which parts of the code were not exercised so the team can target remaining gaps.
It shows strong overall test reach while still revealing a few lines that deserve additional attention.
It gives operators and teammates one repeatable entry point for running the full test workflow.
It reinforces how confident releases depend on layered testing, not just manual checks or a single test type.