Explore unit testing in PHP through practical examples in this 56-minute conference talk from PHP UK Conference 2017. Learn how to transition from manual var_dump debugging to automated testing, starting with basic concepts and progressing to more advanced techniques. Discover strategies for writing effective test cases, improving existing code, and implementing regression tests. Examine real-world scenarios including e-commerce and catalog imports to understand how to apply testing principles. Gain insights on cyclomatic complexity, execution paths, and decision branches to optimize your test coverage. Delve into preemptive debugging techniques and learn how to effectively use mocks for dependencies. By the end of this talk, acquire the skills to confidently implement Test-Driven Development (TDD) while meeting tight deadlines.