1. Quality in PHP projects beyond Unittests
International PHP Conference 2008
October 30th 2008 | Thorsten Rinne

2. Introduction
❙ Thorsten Rinne
❙ 31 years old
❙ Senior Developer and Team Lead at Mayflower GmbH
❙ Reporting applications
❙ Rating applications
❙ PHP consulting for QA and migration problems
❙ PHP software development since 1999
❙ Founder and main developer of open source FAQ
management software phpMyFAQ since 2001
❙ Zend Certified Engineer (PHP 5)
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 2

3. Introduction
❙ Warm up
❙ Quality Criterias
❙ Quality Metrics
❙ Testing
❙ PHP Source Code Quality
❙ Questions and answers
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 3

4. Who are you?
❙ What's your profession?
❙ Software company or agency?
❙ What's your team size?
❙ Who develops using Unittests?
❙ Who uses QA supporting tools?
❙ What's your test coverage?
❙ Even for legacy code? :-)
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 4

5. Quality Criterias
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 5

6. Quality criterias:
Understandability
❙ Availability of documentation
❙ Good documentation quality
❙ Complexity of software
❙ Code commenting and formatting
❙ Understandable naming
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 6

7. Quality criterias:
Completeness
❙ Everything is already there
❙ Your application is fully implemented
❙ No mockups or temporary solutions left
❙ External interfaces are usable
❙ All needed data is available
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 7

8. Quality criterias:
Conciseness
❙ No unneeded, overlong documentation
❙ Especially auto-generated documentation
❙ No unused libraries
❙ No dead code
❙ No duplicate code
❙ No code inside loops that could be outside
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 8

9. Quality criterias:
Portability
❙ Easy to configure in new environments
❙ Few OS and webserver dependencies
❙ Few, documented version dependencies
❙ Language version
❙ Database version
❙ External libraries
❙ Able to survice environment updates
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 9

10. Quality criterias:
Consistency
❙ Predictability
❙ Directory paths and filenames
❙ Class and method names
❙ Variable and constant names
❙ Documentation style and language
❙ Coding style
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 10

11. Quality criterias:
Maintainability
❙ Easy to install and easy to upgrade
❙ Tests and debug logs to help to locate bugs
❙ Few dependencies hiding the bug
❙ No complex dependencies or effects on the platform
❙ Easy to understand and navigate source code
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 11

12. Quality criterias:
Testability
❙ Known acceptence criteria
❙ Adequate separation of concerns
❙ Easy to use interfaces for tests
❙ No limiting dependencies
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 12

13. Quality criterias:
Reliability
❙ The criteria formerly known as „robustness“
❙ Fault tolerance
❙ Graceful degradation
❙ Exception handling exists
❙ Is method input checked?
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 13

14. Quality criterias:
Usability
❙ Learnability: Easyness of first time usage
❙ Efficiency: Overall speed of usage per task
❙ Memorabilty: Time to re-establish usage knowledge after
absence
❙ Errors: Frequency of usage errors
❙ Satisfaction: Fun to use the software
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 14

15. Quality Metrics
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 15

16. Quality Metrics:
Defect Density Metrics
❙ Code-based metric
❙ Defects per KSSI (1000 shipped source instructions) for
product quality
❙ Defects per KCSI (1000 changed source instructions)
for development quality
❙ (Hard to measure)
❙ Statistic needed
❙ easier for products
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 16

17. Quality Metrics:
Customer Problem Metrics
❙ PUM: Problems per user month
❙ Defects per month / number of installations
❙ Maintainance metric: Number of bugs closed / number of
bugs arrived
❙ The customer does not care how big or how complicated
the software is :-)
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 17

18. Quality Metrics:
Customer Satisfaction Metrics
❙ You only get them by survey
❙ for
❙ Functionality
❙ Usability
❙ Reliability
❙ Performance
❙ Maintainability
❙ Service
❙ Levels: Very Satisfied, Satisfied, Neutral, Dissatisfied, Very
Dissatisfied
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 18

19. Quality Metrics:
When are bugs detected?
❙ Number of pre-release bugs found while testing
❙ Number of post-release bugs
❙ found by customer
❙ found by testing
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 19

20. Quality Metrics:
How are defects fixed?
❙ Average Time to fix a bug
❙ Average Time for bugfix release
❙ that‘s the time relevant for the customer
❙ Average engineering hours / fixed defect
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 20

21. Quality Metrics:
Defect Impact
❙ was the defect visible to the user?
❙ has a monetary transaction been touched?
❙ has sensitive data been touched?
❙ are there security implications?
❙ has there been a marketing/image effect
❙ did data / user work get lost?
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 21

22. Quality Metrics:
Testing Efficiency
❙ Found bugs before release / found bugs post release
❙ Found bugs by qa team / found bugs by customer
❙ Number of bugs found by QA Team / time
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 22

23. „We do PHPUnit!“ !== Testing
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 23

24. Unit Testing
❙ For PHP: PHPUnit or SimpleTest
❙ Focussing on testing a single unit of work
❙ solves depencies using mock objects
❙ should not depend on database
❙ perfect and easy to automate
❙ Reason for all refactoring
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 24

25. Acceptence Testing
❙ originally user acceptance testing
❙ one of the final testing stages
❙ change to automated black box testing in agile
environments
❙ used to test user stories
❙ often contractual requirement
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 25

26. SOA / Service Testing
❙ in multi-tier environments every service can have several
consumers
❙ black box test for the service api
❙ can easily be automated
❙ a lot of tools for SOAP
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 26

27. Integration Testing
❙ tests the application with all parts
❙ needed for multi-tier applications
❙ tests the interaction paths
❙ intersection with load testing: user simulation
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 27

28. Load Testing
❙ Simulates high load situations
❙ to detect the current platform abilities
❙ to detect resource bottlenecks (Database, CPU,
Network)
❙ to detect concurreny bottlenecks (locking jams, caching
effects)
❙ Scalability testing: scale up or scale out?
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 28

29. Usability Testing
❙ How does the user work with the application?
❙ Efficiency: time to fulfill a basic task
❙ Accuracy: how many mistakes happened?
❙ Recall: does the user recall the usage after a period of
time?
❙ Emotional response: does the user feel lucky, confident or
stressed about the task?
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 29

30. Regression Testing
❙ originally: if you find a bug, fix it and write a test
❙ PHP itself does it
❙ now often written by the test team to assure the expected
default behavior
❙ modern: automated test generation
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 30

31. Security Testing
❙ Blackbox: Penetration Test done by external auditor just
before release
❙ Graybox: using tools like fuzzers and scanners before
release or while development
❙ Whitebox: internal or external source code audit, static
code analysis while development
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 31

32. A lot more ...
❙ Compability testing for maintainability
❙ Volume testing for bigger amounts of data
❙ Stress testing for degrade and failover processes
❙ Installation testing for maintenance
❙ Recovery testing to check recovery behavior
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 32

33. PHP Source Code Quality
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 33

34. Documentation
❙ We have different forms of documentation:
❙ Inline documentation
❙ API documentation
❙ Developer documentation
❙ Security documentation
❙ Administration documentation
❙ End-user documentation
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 34

35. Coding Style / Formatting
❙ Coding style is defined in the developer documentation
❙ All developers have to write their code formatted in the
given coding style
❙ Can be checked by CodeSniffer tools
❙ Coding style should be based on your main used libraries
❙ If you build your application on top of the Zend
Framework, use the ZF coding style
❙ With IDEs like Eclipse you can format old code
autpmatically
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 35

36. Naming Conventions
❙ Naming conventions are very important
❙ NonamespacesbeforePHP5.3
❙ Easier for __autoload()
❙ Examples
❙ Class names:
❙ class HTML_Template_ITX2
❙ Directory: include/PEAR2/HTML/Template/ITX2.php
❙ Function names in camel caps:
❙ public function blockExists($blockname)
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 36

37. Code Complexity
❙ Complexity costs time and money if you don‘t need it
❙ KISS principle: Keep it simple and stupid
❙ Complexity checks by CodeSniffer metrics
❙ Important for good code coverage and unittests
❙ Examples
❙ Too high number of linearly independent paths through
a program's source code
❙ Too long class and method names
❙ Too many properties
❙ Too many parameters
❙ Too many methods inside a class
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 37

38. Anti Patterns
❙ An antipattern is a design pattern that appears obvious but
is ineffective or far from optimal in practice
❙ Examples
❙ Unnecessary abstraction
❙ God objects
❙ Spaghetti code
❙ Too short or too long variable names
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 38

39. Anti Pattern Examples
❙ if(<EXPR>) {<empty>}
❙ if(<EXPR>) {<EXPR>} else {<empty>}
❙ try(<EXPR>) {<empty>}
❙ try(<EXPR>) {<EXPR>} catch(Exception $e)
{<empty>}
❙ define('SOME_NAME', $var)
❙ include[_once]|require[_once]|readfile|
virtual|file_get_contents|fopen|file|
mysql_query($_GET|$_POST|$_REQUEST)
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 39

40. Questions?
Quality in PHP projects
beyond Unittests
© MAYFLOWER GmbH 2008 40

41. Thank you very much!
Thorsten Rinne
Mayflower GmbH
Mannhardtstr. 6
80538 München
+49 (89) 24 20 54 - 31
thorsten.rinne@mayflower.de