python-module-to-package-refactor

When splitting a Python module into a package, unittest.mock.patch targets break because they still refer to the old flat module path instead of the actual runtime lookup path. You must update patch targets to reflect where names are now looked up within the restructured package.

To update mock.patch targets during a module-to-package refactor, change the patch paths to point to the actual module attribute location where the name is looked up at runtime. This ensures patches resolve correctly after restructuring.

The best way to migrate a large Python module into a package without breaking tests is using a bottom-up migration approach. Create the package structure with __init__.py re-exports and comprehensively verify patch paths across all test suites.

Yes, you need to wire re-exports in __init__.py when refactoring a Python module into a package. This preserves test compatibility and ensures existing imports resolve correctly while you update patch targets across multiple modules.

Yes, a bottom-up migration approach works for Python package refactors with multiple interdependencies. It enforces creating the package structure first, wiring __init__.py re-exports, and then validating patch paths across test suites to preserve behavior.

If patch paths do not resolve to the correct module attributes after a package refactor, unit tests will fail because mocks target the wrong lookup path. Comprehensive patch-path verification across all tests is required to preserve test reliability.