Continuous Integration in PHP
Why, what and how?
Wilco Jansen
October 4th 2009
Tdose, at the Fontys University of
Applied Science in Eindhoven, Netherlands

Wilco Jansen
Formerly Involved in Joomla
• Board member Open Source matters
• Core team member
• (first ever) Development coordinator
• Creator of the Joomla bug-squad
• Google Summer of Code program
manager 2006, 2007 and 2008 editions
• Google Highly Open participation content program manager in
2008

This presentation is about development tools

Continuous integration in PHP

That help build better software in PHP

Things to think about before you run out of time...

Tools will solve some problems

Why use continuous integration?
● The earliest possible detection of problems in the software
● Detection of integration problems, no last minute hiatus
before releases
● Early warning of broken/incompatible code
● Early warning of conflicting changes
● Immediate unit testing of all changes
● Constant availability of a “current” build for testing, demo
or release purposes
● The immediate impact of checking in incomplete or broken
code acts as an incentive to developers to learn to work
more incrementally with shorter feedback cycles

Why use continuous integration?

The classic approach

The classic approach
● Write a test program (or be the tester)
● Run the test program (or perform the test
yourself)
● Manually verify the output
● Delete the test program

A fundamental shift

Continuous integration emerged from Extreme
programming

Question you would like to answer...

Does my code work?
And
Does it still work after I committed new code?

Agile approach

Write a unit test!
● Executable specification
● Automatic evaluation
● A simple test environment
● Instant feedback
● Used as regression test

Detect problems in the earliest possible stage

● Defacto standard for unit testing of PHP
applications
● Member of the xUnit family
● Inspired by tools like Junit, TestNG, Junitour,
JExample etc.
● Latest stable version 3.4.0 (released 16
September 2009)

Things to keep in mind...

Unit tests should run in less than 1 ms

Software testing categories
● Small – Unit tests
● Check conditional logic in the code
● No debugger required
● Runs in less than 1 ms
● Small – Functional tests
● Check whether the interface between classes abide
by their contacts

Does PHP Unit only run tests?

Other things PHPUnit can do
● Skeleton generation
● Integration of Selennium

PHP Unit and code coverage analyses

PHP Unit and code coverage analyses
● Helps you with analyzing which statements,
branches and paths are executed within the
test run:
● Statement coverage
● Branch coverage
● Path coverage
● 100% code coverage is preferred, but does not
say anything about the test completeness!

Coding standards...

PHP Code Sniffer (phpcs)

PHP Code Sniffer “Sniffs”...
● PHP
● Javascript
● CSS
To detect violations of defined coding standards
with as main goal to ensure code remains clean
and consistent.
Following coding standards are default available:
MySource, PHPCS, Zend, PEAR and Squiz

An example run

Other available tools
● PHP copy/paste detector
● PHP Depend – software metric tool
● PHP Loc – Lines of code analyses
● PHP PMD – Project Mess Detector
Note: only copy/paste detection will be part of this presentation

Copy/paste detection

Code duplication (phpcd)
● Code is marked duplicate when two sequences
of code are:
● Textually identical
● Token for token identical
● Functionally identical
● Problems
● Duplication of code contradicts code reuse
● Co-evolution of clones hinders maintenance

Example run

How it all can be put together?

Pick your continuous build environment

General mode of operation
● Developer commits code
● Commit triggers a build (initiated by versioning
system, or by polling the version system)
● Build script is run
● Output is processed, notification send

Cruisecontrol and PHPUndercontrol

Ant is used to process the build

Remember...

A fool with a tool is still a fool!

One of the hardest things to express about
continuous integration is that makes a
fundamental shift to the whole development
pattern, one that isn't easy to see if you've never
worked in an environment that practices it. In fact
most people do see this atmosphere if they are
working solo - because then they only integrate
with themselves. For many people team
development just comes with certain problems
that are part of the territory. Continuous
integration reduces these problems, in
exchange for a certain amount of discipline.

The end...
Acknowledgement Links
● Part of this presentation was inspired ● PHPUnit - http://www.phpunit.de
by “The State of QA Tools for PHP” ● PHP Code sniffer -
from Sabastian Bergmann
http://pear.php.net/package/PHP_CodeSniffer/
About me and this presentation ● PHP copy/paste detector -
● Personal blog can be found on http://github.com/sebastianbergmann/phpcpd/
http://www.jfoobar.org ● Cruisecontrol -
● Slides will be uploaded to http://cruisecontrol.sourceforge.net/
http://slideshare.net/willebil ● PHP Under control - http://phpundercontrol.org/
● Follow me on twitter: ● Bamboo -
http://twitter.com/willebil
http://www.atlassian.com/software/bamboo/
● PHP lines of code -
http://github.com/sebastianbergmann/phploc