TDD BDD PHP

1
TDD - BDD - PHP

• Bill Barnett
• ltbilly_at_booksmartbilly.comgt
• OINK-PUG January 2008

2
Who Am I?

• OINK-PUG's Founder
• Lead Systems Analyst - SCRIP-SAFE International
• PHP programmer for profit Ruby for fun.
• Bourbon Drinking, Hockey Playing, Former Marine
• Epicurean Night Owl with a Conservative Streak

3
Who Are You?(Who? Who? Who? Who?)

• Beginning to use PHP's advanced features.
• Sleepless the night of a release.
• Overworked the day after.
• Looking for a better way.
• With a certain probability, not named Jerry.
• Not currently using TDD or BDD.

4
Idiocy

• "Never underestimate the power of stupid people
  in large groups."
• (calendar.despair.com)

5
PHP5

• Released July 2004
• Advanced Language Features
• Constructors Destructors
• Public, Protected, Private properties and
  methods
• Interfaces Abstract classes
• Static properties and methods
• Final properties and methods

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PHP5

• Enhanced MySQL Support
• Prepared Statements
• Bound Input Output Parameters
• Multi-Query Functions
• SSL

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PHP5

• XML Rebuilt
• W3 Compliant
• Standardized in libxml2
• Parse Alter with SimpleXML
• Reworked DOM XSL Extensions

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PHP5

• And More...
• SQLite Embedded
• Reworked Error Handlers Exceptions
• SOAP
• Iterators

9
Cluelessness

• "There are no stupid questions, but there are a
  LOT of inquisitive idiots."
• (calendar.despair.com)

10
Traditional Approach

• Waterfall Methodology (Sequential)
• Requirements Gathering
• Big design ("The Spec")
• Coding ("Implementation")
• Testing
• Integration
• Maintenance

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Advanced Programming Methodologies

• Iterative Shorten the feedback loop
• Agile Software Development
• eXtreme Programming (XP)
• SCRUM
• Test Driven Development
• Behavior Driven Development

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Test Driven Development

• Kent Beck Ward Cunningham
• Features begin life as tests
• "Red, Green, Refactor"
• Write a test watch it fail (Red)
• Write some code watch it pass (Green)
• Refactor Repeat

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Test Driven Development

• Unit Testing (xUnit)
• Functional Testing (We're not going there!)
• Popular PHP Testing Frameworks
• PHPUnit
• SimpleTest
• lime

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What makes a good framework?

• Assertions
• Test grouping or suites
• Data providers or fixtures
• Mocking

15
Lets code!
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Meetings

• "None of us is as dumb as all of us."
• (calendar.despair.com)

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Benefits of Unit Testing

• As much about design as testing
• Forms a basis for refactoring (think improvement
  AND extension)
• Builds confidence and reduces stress
• Can serve as a documentation source
• Can help ensure minimum code is written

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Testing Pitfalls

• Test the application, not the framework.
• How do you define a unit in testing?
• How do I know Im testing enough?
• Can I test too much?
• What is the link between what is tested and how
  the application is supposed to work?

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Behavior Driven Development

• Intended to address a basic flaw in TDD
• Focus on application behavior
• Specifications as tests
• Specification, not verification
• Domain Specific Language
• Sapir-Whorf

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BDD Frameworks for PHP

• PHPSpec
• Extensions of PHPUnit and lime?
• Thats all (for now) folks!

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PHPSpec

• Identify a valuable behavior you want to
  implement
• Describe it in plain text in the form "it should
  ... ", i.e. a specification
• Write one or more specs/examples for the "it
  should" components of your specification
• Implement the behavior you've just described in
  the specification
• Refactor the implemented code if needed
• Return to Step 1

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Lets code some more!
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Adversity

• "That which does not kill me simply postpones the
  inevitable."
• (calendar.despair.com)

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What Now?How do I start?

• Got a bug? Write a test!
• Test the 10. (10 of the code does 90 of the
  work.)
• Comment function contents.
• Uncomment and test logic branches.
• Repeat for nested branches until done.
• "Some tests" is better than "no tests."

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Review

• PHP is a FWWTBR among scripting languages.
• As such, PHP devs can easily get in "over their
  heads."
• TDD BDD can help you sleep better, will win you
  the respect of your peers, and get you dates.
• TDD BDD are not widely accepted or used by PHP
  developers at any level.
• YMMV.

"Force with which to be reckoned." (Props to my
mom, the English teacher.)
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Questions?

• Links
• PHPUnit http//www.phpunit.de/pocket_guide/
• SimpleTest http//simpletest.sourceforge.net/en/o
  verview.html
• lime http//www.symfony-project.org/book/1_0/15-U
  nit-and-Functional-Testing
• PHPSpec http//dev.phpspec.org/manual/en/index.ht
  ml