TDD in PHP - A Brief Example (Nashville PHP 2010-10-12)
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TDD in PHP - A Brief Example (Nashville PHP 2010-10-12)






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    TDD in PHP - A Brief Example (Nashville PHP 2010-10-12) TDD in PHP - A Brief Example (Nashville PHP 2010-10-12) Presentation Transcript

    • TDD in PHP: A Brief Example
    • About Me Jeremy Kendall PHP Developer since 2001 Organizer Memphis PHP Contributor to FRAPI project ( [email_address] @JeremyKendall
    • TDD in PHP: A Brief Example Test Driven Development, you say?
    • Frankly, my dear . . .
    • Why You Should Give A Damn
        Test Driven Development is perhaps one of the best and fastest ways to improve your understanding and command of object-oriented principles and best practices. ” Good design is testable, and design that isn't testable is bad.” - Michael C. Feathers
    • What is TDD?
      • From Wikipedia:
      • ” Test Driven Development (TDD) is a software development process that relies on the repetition of a very short development cycle . . .”
    • TDD Development Process
      • Write a test
      • Run all tests, watch new test fail
      • Write just enough code to make the test pass
      • Run all tests, watch new test pass
      • Lather, rinse, repeat . . .
      • Refactor
    • TDD: The Benefits
      • High cohesion, loose coupling
      • Confidence
      • Faster time to resolution
      • Documentation
    • TDD: The Drawbacks
      • Tests only cover what you think should be tested
      • False sense of confidence
      • Without management and team buy-in, TDD is DOA
    • TDD: Live Code Example
        Live Coding? Really? Why?
    • TDD: Live Code Example
      • Goals
        • Practical example of TDD in action
        • Demonstrate refactoring with confidence
        • Demonstrate TDD impact on design decisions
    • TDD: Live Code Example
      • Code example will test a fictional math tutor application
        • Calculator class
        • Tutor class (consumes calculator)
    • TDD: Live Code Example
      • Calculator class
        • Adds one integer to another
        • Throws exceptions in the following cases:
          • Non-integer arguments provided
          • Integer overflow
          • Integer underflow
        • Code to interface not implementation
          • Tutor_Calculator_Interface
          • Tutor_Calculator_IntegerCalculator
    • TDD: Live Code Example
      • Tutor class
        • Verifies correct responses
        • Uses calculator class to test responses
        • Favors composition over inheritance
        • Tutor_MathTutor
    • TDD: Live Code Example
      • We'll be using PHPUnit
      • PHPUnit will be configured with phpunit.xml
      • phpunit.xml:
        • Calls bootstrap.php
        • Tells PHPUnit where to look for our tests
        • Code coverage and testdox reports
      • bootstrap.php:
        • Adds our library to the include path
        • Registers a simple autoloader
    • LET'S GET IT ON!
    • Resources
      • Test Driven Development at Wikipedia -
      • PHPUnit -
      • Xdebug -
      • The code example in this presentation was adapted for PHP from Przemysław Bielicki's TDD video tutorial at Agile Software Development. -
    • Thanks!
        [email_address] @JeremyKendall