Pytest pt3 - Writing Cleaner Tests with Parametrization and Temporary Files

Short summary

Part 3 of a pytest series covers parametrization and temporary file management for data engineering test suites. The author demonstrates replacing conditional test branching with declarative @pytest.mark.parametrize tables, using patch.multiple for cleaner multi-dependency mocking, and leveraging tmp_path fixtures to prevent test artifact leakage between runs. Concrete code examples show testing data transformation functions and S3 readers with proper isolation.

• •Use @pytest.mark.parametrize with explicit ids to replace conditional branching and get clear failure reports
• •Use patch.multiple or stacked @patch decorators for cleaner multi-dependency mocking
• •Use tmp_path fixtures to automatically clean up test artifacts and prevent inter-run pollution

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