An introduction to how to write clean code (type hinting, docstrings, inline comments et cetera) and supporting the clean code with maintainable project structure and unit tests. Goals - with comparisons/examples: What's clean, maintainable code? (type hinting, docstrings, inline comments et cetera) What's a clean, navigatable project structure? Should the tests package be nested into each package? Should my 'tests' package structure mirror the project structure? (for easy navigation of which module/package is being tested) (Testing) What should I test and what shouldn't I test? (Testing) When should I mock and when shouldn't I? (Testing) Writing clean test cases (Testing) Using pytest to utilize parametrize to test multiple combinations, whilst keeping a clean codebase