Testing Craft

Choose tests for the defects they catch. Preserve useful regression coverage without binding tests to incidental implementation details.

Scope and verification

Identify the behavior being changed and the specific defect each new or modified test should catch. A test need not detect unrelated defects.
Follow project instructions and existing test conventions over these defaults.
Run affected tests and required checks. Broaden coverage when the change's dependencies, failures, or unresolved risks justify it.
Do not change production architecture merely to satisfy a testing preference. Restructure when needed for the requested fix; propose independent refactors.
Read only the relevant language file below when runner or fixture guidance is needed. General code guidance lives in code-craft.