Require Test Coverage

Generate test coverage by importing and testing EXISTING production code. Tests must invoke real production functions, not reimplement business logic.

Requirements:
- Import production functions, methods, and classes directly from source modules
- Test structure must contain only: imports, test setup/fixtures, function invocation, and assertions
- Mock or stub ONLY external dependencies (APIs, databases, file systems, network services)
- Test assertions must validate return values and side effects of actual production code execution
- Do not recreate algorithms, calculations, or business logic from production code inside test files

Forbidden Patterns:
- Copying or paraphrasing function logic into test files
- Creating test-local implementations that duplicate production behavior
- Mocking the internal function or method under test
- Inlining expected output derived from reimplemented logic instead of calling the production function

Validation Gate: Flag any test file where business logic appears outside of imports, setup, invocation, or assertions. A test that computes expected values by reimplementing production algorithms instead of calling the production function fails review.