Dive into a comprehensive 4.5-hour PHP eCommerce project tutorial series, focusing on Object-Oriented Programming (OOP) beyond the basics and Test-Driven Development (TDD). Learn to build a robust eCommerce application using PHP, Doctrine ORM, and PHPUnit. Cover essential topics including session management, user authentication, database interactions, product and order management, and custom PHPUnit assertions. Explore user experience (UX) considerations and best practices for developing a minimal viable product. Gain hands-on experience in creating and testing various components of an eCommerce system, from user creation to order processing, while improving code quality and maintainability.