Writing and Refactoring Testable PHP

Discover how to leverage test-driven development (TDD) in new PHP projects and refactor code in existing projects.

Introduction

• Test-driven development and refactoring in PHP
• Concepts and technologies you should know
• Using GitHub Codespaces with this course

1. What Are You Doing Here?

• Automated testing
• Define types of testing
• What is refactoring?
• When to refactor

2. TDD a New Project

• Configure a project for tests
• Write an acceptance test
• Write a failing unit test, make the test pass, refactor
• Write testable code

3. What to Refactor in Existing (Legacy) Projects

• Large chunks of logic
• Incorrect OOP logic
• Change lots of files for one feature
• Unnecessary code
• Strong coupling
• Using mocks
• Files that are modified often
• Identifying the best place to start

4. Examples of Test-Driven Refactoring

• Add one passing test
• Identify a brittle function and add tests
• Extract functionality (using TDD)
• Simplify conditionals
• Simplify function signatures

5. OOP Examples of Test-Driven Refactoring

• Identify objects from related functions
• Replace arrays with objects
• Add value objects (easy to test)
• Add null objects
• Replace conditionals with interfaced classes

6. Moving Fast by Moving Slower

• Make steady progress
• Prevent regressions
• Cleaner code
• Decoupled code
• Become a better developer

7. TDD and Refactoring in the Real World

• On a spaghetti-code project
• With a looming deadline
• With a team that doesn't understand TDD and refactoring
• With a PM that doesn’t understand TDD and refactoring

Conclusion

• Next steps