Agility and Quality

Agility and QualitySebastian Bergmann February 25 th 2011

Hello! My name is Sebastian. Sebas tian

Hello! My name is Sebastian …and this is what I do: sebastian@thePHP.cc Co-Founder of The PHP Consulting Company sebastian@phpunit.de Creator and Main Developer of PHPUnit sebastian@php.net Contributor to PHP sebastian@apache.org Contributor to Zeta Components sbergmann@{acm.org | ieee.org} Practitioner of academic computing

If the project manager loses aggro (when the client targets the developers) then Roleplaying Software Developmentyou wipe.http://www.ampelofilosofies.gr/software/2010/11/15/roleplayingsoftwaredevelopment/

Your project manager is your tank.If the project manager loses aggro (when the client targets the developers) then you wipe. This slide contains material by Vassilis Rizopoulos

Your operations engineers are your healers.If operations gets aggro (when flaky infrastructure disrupts the team) then you wipe. This slide contains material by Vassilis Rizopoulos

The coders and testers are your damage dealers.If the developers are working on multiple tasks then the tank wont hold for long and you wipe. This slide contains material by Vassilis Rizopoulos

The ”Time, Money, Quality – Pick two” Fallacyhttp://www.startuplessonslearned.com/2008/10/engineeringmanagerslament.html

Agile EnvironmentsScrum is an agile method for project management. http://en.wikipedia.org/wiki/File:Scrum_process.svg

Agile EnvironmentsScrum is not an agile method for software engineering. http://en.wikipedia.org/wiki/File:Scrum_process.svg

Agile EnvironmentsCommon elements of agile software development Coding  Collective Code Ownership  Test-Driven Development  Continuous Integration & Continuous Inspection Testing  All code must have unit tests  All code must pass all unit tests before release  When a bug is found, tests are created Operations  Continuous Deployment & Continuous Delivery

Agile development puts a focus on software quality.

Software QualityExternal Quality Internal Quality Functionality  Working code that is Usability  unique (not duplicated) Reliability  simple (not complicated) Performance  clear (not puzzling) Supportability  easy to adapt and extend This slide contains material by Jeff Langr and Tim Ottinger

TestDriven DevelopmentDisciplined software development practicethat focuses on software designby first writing automated unit testsfollowed by production codein short, frequent iterations This slide contains material by David S. Janzen

TestDriven Development Fewer defects Fewer statements Lower computational complexity Lower coupling between classes Higher test coverage and volume This slide contains material by David S. Janzen

Unit Tests test a unit of code isolated from its dependencies can be read as an executable specification are automatically evaluated and repeatable need only a simple test environment provide instant feedback are written with the code, not after the code are kept as regression test

The BankAccount exampleBankAccountTest.php<?phpclass BankAccountTest extends PHPUnit_Framework_TestCase{ public function testBalanceIsInitiallyZero() { $ba = new BankAccount; $this->assertEquals(0, $ba->getBalance()); }}

The BankAccount exampleRunning the test(s)sb@ubuntu ~ % phpunit BankAccountTestPHPUnit 3.5.12 by Sebastian Bergmann..Time: 0 seconds, Memory: 3.25MbOK (1 test, 1 assertion)

The BankAccount exampleTests can serve as an executable specification.

The BankAccount exampleTests can serve as an executable specification.sb@ubuntu ~ % phpunit --testdox BankAccountTestPHPUnit 3.5.12 by Sebastian Bergmann.BankAccount [x] Balance is initially zero

Static Code Analysis

Static Code AnalysisHow much code do we have?sb@thinkpad bankaccount % phploc --count-tests .phploc 1.6.1 by Sebastian Bergmann.Directories: 13Files: 39Lines of Code (LOC): 1330 Cyclomatic Complexity / Lines of Code: 0.04Executable Lines of Code (ELOC): 697Comment Lines of Code (CLOC): 214Non-Comment Lines of Code (NCLOC): 1116Namespaces: 0Interfaces: 1Classes: 20 Abstract: 1 (5.00%) Concrete: 19 (95.00%) Average Class Length (NCLOC): 51Methods: 34 Scope: Non-Static: 34 (100.00%) Static: 0 (0.00%) Visibility: Public: 23 (67.65%) Non-Public: 11 (32.35%) Average Method Length (NCLOC): 30 Cyclomatic Complexity / Number of Methods: 1.68Anonymous Functions: 1Functions: 0Constants: 0 Global constants: 0 Class constants: 0Tests: Classes: 16 Methods: 40

Static Code AnalysisHow is the code structured? sb@thinkpad bankaccount % phploc --count-tests . phploc 1.6.1 by Sebastian Bergmann. Directories: 13 Files: 39 Lines of Code (LOC): 1330 Cyclomatic Complexity / Lines of Code: 0.04 Executable Lines of Code (ELOC): 697 Comment Lines of Code (CLOC): 214 Non-Comment Lines of Code (NCLOC): 1116 Namespaces: 0 Interfaces: 1 Classes: 20 Abstract: 1 (5.00%) Concrete: 19 (95.00%) Average Class Length (NCLOC): 51 Methods: 34 Scope: Non-Static: 34 (100.00%) Static: 0 (0.00%) Visibility: Public: 23 (67.65%) Non-Public: 11 (32.35%) Average Method Length (NCLOC): 30 Cyclomatic Complexity / Number of Methods: 1.68 Anonymous Functions: 1 Functions: 0 Constants: 0 Global constants: 0 Class constants: 0 Tests: Classes: 16 Methods: 40

Static Code AnalysisHow is the code structured? sb@thinkpad bankaccount % pdepend --overview-pyramid=pyramid.svg src ANDC Average Number of Derived Classes AHH Average Hierarchy Height NOP Number of Packages NOC Number of Classes NOM Number of Methods LOC Lines of Code (non-comment, non-whitespace) CYCLO Cyclomatic Complexity CALLS Number of Operation Calls FANOUT Number of Called Classes

Static Code AnalysisHow is the code executed? 1 <?php 2 class BankAccount 3 { // ...25 protected function setBalance($balance)26 {27 if ($balance < 0) {28 throw new BankAccountException;29 }3031 $this->balance = $balance;32 }33 }

Static Code AnalysisHow is the code executed? sb@thinkpad bankaccount % bytekit --eliminate-dead-code src/model/BankAccount.php Bytekit-cli 1.1.1 by Sebastian Bergmann. . . Function: BankAccount::setBalance Number of oplines: 16 Compiled variables: !0 = $balance line # opcode result operands ----------------------------------------------------------------------------- 25 0 EXT_NOP 1 RECV !0 1, f(0) 27 2 EXT_STMT 3 IS_SMALLER ~0 !0, 0 4 JMPZ ~0, ->13 28 5 EXT_STMT 6 FETCH_CLASS ~1 BankAccountException, f(4) 7 EXT_FCALL_BEGIN 8 NEW $2 ~1, ->10 9 DO_FCALL_BY_NAME 10 EXT_FCALL_END 11 THROW $2 31 12 EXT_STMT 13 ASSIGN_OBJ balance, !0 32 14 EXT_STMT 15 RETURN null

Static Code AnalysisHow is the code executed? sb@thinkpad bankaccount % bytekit --graph . --format svg --eliminate-dead-code src/model/BankAccount.php 00000800 00000800 EXT_NOP 00000801 RECV !0 1, f(0) 00000802 EXT_STMT 00000803 IS_SMALLER ~0 !0, 0 00000804 JMPZ ~0, loc_80d0000080500000805 EXT_STMT 0000080d00000806 FETCH_CLASS ~1 BankAccountException, f(4) 0000080d EXT_STMT00000807 EXT_FCALL_BEGIN 0000080e ASSIGN_OBJ balance, !000000808 NEW $2 ~1, loc_80a 00000810 EXT_STMT00000809 DO_FCALL_BY_NAME 00000811 RETURN null0000080a EXT_FCALL_END0000080b THROW $2

Static Code AnalysisCan we find ”interesting” code using tools? sb@thinkpad bankaccount % phpcs --standard=CodeReview --extensions=php --report=source src

Static Code AnalysisCan we find ”interesting” code using tools? sb@thinkpad ~ % phpcs --standard=CodeReview --extensions=php --report=source typo3-4.4.2 PHP CODE SNIFFER VIOLATION SOURCE SUMMARY -------------------------------------------------------------------------------- STANDARD CATEGORY SNIFF COUNT -------------------------------------------------------------------------------- Generic PHP No silenced errors 1055 Generic Metrics Cyclomatic complexity 746 Generic Code analysis Unused function parameter 624 Generic Metrics Nesting level 299 Generic Code analysis For loop with test function call 76 Generic Code analysis Empty statement 64 Generic Code analysis Useless overriding method 7 Generic Code analysis Jumbled incrementer 3 Generic Code analysis Unconditional if statement 3 Generic Code analysis For loop should be while loop 1 -------------------------------------------------------------------------------- A TOTAL OF 2878 SNIFF VIOLATION(S) WERE FOUND IN 10 SOURCE(S) --------------------------------------------------------------------------------

Static Code AnalysisCan we find ”interesting” code using tools? sb@thinkpad ~ % phpcs --standard=CodeReview --extensions=php typo3-4.4.2 FILE: /home/sb/typo3/index.php -------------------------------------------------------------------------------- FOUND 0 ERROR(S) AFFECTING 2 LINE(S) -------------------------------------------------------------------------------- 57 | WARNING | Silencing errors is discouraged 59 | WARNING | Silencing errors is discouraged -------------------------------------------------------------------------------- FILE: .../sb/typo3/t3lib/cache/backend/class.t3lib_cache_backend_filebackend.php -------------------------------------------------------------------------------- FOUND 1 ERROR(S) AFFECTING 4 LINE(S) -------------------------------------------------------------------------------- 89 | ERROR | Empty CATCH statement detected 105 | WARNING | Functions cyclomatic complexity (17) exceeds 10; consider | | refactoring the function 327 | WARNING | Avoid function calls in a FOR loop test part 358 | WARNING | Avoid function calls in a FOR loop test part -------------------------------------------------------------------------------- . . .

Static Code AnalysisCan we find ”interesting” code using tools? sb@thinkpad ~ % phpmd typo3-4.4.2 text codesize,design,naming,unusedcode t3lib/class.t3lib_sqlengine.php:104 This class has a bunch of public methods and attributes t3lib/class.t3lib_sqlengine.php:104 This class has too many methods, consider refactoring it. t3lib/class.t3lib_sqlengine.php:104 This class t3lib_sqlengine has an overall complexity of 105 which is very high. The configured complexity threshold is 50. t3lib/class.t3lib_sqlengine.php:126 Avoid unused parameters such as $config. t3lib/class.t3lib_sqlengine.php:126 Avoid unused parameters such as $pObj. t3lib/class.t3lib_sqlengine.php:150 The method processAccordingToConfig() has a Cyclomatic Complexity of 15. t3lib/class.t3lib_sqlengine.php:227 Avoid unused local variables such as $options. t3lib/class.t3lib_sqlengine.php:383 Avoid unused parameters such as $select_fields. t3lib/class.t3lib_sqlengine.php:383 Avoid unused parameters such as $groupBy. t3lib/class.t3lib_sqlengine.php:383 Avoid unused parameters such as $orderBy. t3lib/class.t3lib_sqlengine.php:383 Avoid unused parameters such as $limit. t3lib/class.t3lib_sqlengine.php:426 Avoid unused parameters such as $query. t3lib/class.t3lib_sqlengine.php:502 Avoid unused parameters such as $tableName. t3lib/class.t3lib_sqlengine.php:513 Avoid unused parameters such as $tableName. t3lib/class.t3lib_sqlengine.php:629 The method select_evalSingle() has a Cyclomatic Complexity of 38. t3lib/class.t3lib_sqlengine.php:629 The method select_evalSingle() has an NPath complexity of 3980. t3lib/class.t3lib_sqlengine.php:629 Avoid really long methods. t3lib/class.t3lib_sqlengine.php:835 Avoid excessively long variable names like $TYPO3_DBAL_handlerType . . .

Static Code AnalysisDo we have duplicated code? sb@thinkpad ~ % phpcpd typo3-4.4.2 phpcpd 1.3.2 by Sebastian Bergmann. Found 80 exact clones with 3415 duplicated lines in 82 files: - t3lib/class.t3lib_fullsearch.php:800-814 t3lib/class.t3lib_querygenerator.php:1409-1423 - t3lib/class.t3lib_tceforms.php:2210-2216 t3lib/class.t3lib_tceforms.php:2322-2328 - typo3/file_edit.php:99-115 typo3/file_rename.php:110-126 . . . 0.93% duplicated lines out of 365956 total lines of code. Time: 01:28, Memory: 359.00Mb

Static Code AnalysisEven more tools  HipHop for PHP: http://bit.ly/HipHop4QA  pfff: http://github.com/facebook/pfff  Phantm: http://github.com/colder/phantm  Padawan: http://github.com/mayflowergmbh/padawan/  php-tracer-weaver: http://github.com/troelskn/php-tracer-weaver/

QA Tools for PHPOverview http://phpqatools.org/

Continuous Integration is aboutfeeling the pulse of a project.

Continuous IntegrationProvides insight into the developmentprogress and code quality throughout thedevelopment lifecycle by automatically fetching new revisions from the version control system running the tests analysing the code collecting and reporting software metrics

Continuous Integration of PHP Projects Jenkins http://jenkins-ci.org/ Template for Jenkins Jobs for PHP Projects http://jenkins-php.org/ PHP Project Wizard (PPW)  https://github.com/sebastianbergmann/php-project-wizard

Continuous Integration of PHP ProjectsAlternative Continuous Integration Servers CruiseControl phpUnderControl Arbit Atlassian Bamboo JetBrains TeamCity

Avoid ”Big Bang” Deployments

Deploy Early, Deploy Often”Software delivers no revenue until it is in the hands of its users. […] For large companies every week of delay between having an idea and releasing the code that implements it can represent millions of dollars in opportunity costs […]” – Jez Humble and David Farley

Deploy Early, Deploy Often”Software delivers no revenue until it is in the hands of its users. […] For large companies every week of delay between having an idea and releasing the code that implements it can represent millions of dollars in opportunity costs […]” – Jez Humble and David Farley”Our highest priority is to satisfy the customer through early and continuous delivery of valuable software.” – Agile Manifesto

Deploy Early, Deploy Often”Flickr was last deployed 6 hours ago, including 5 changes by 3 people.In the last week there were 74 deploys of 447 changes by 22 people.” – http://code.flickr.com/

Deploy Early, Deploy Often”Flickr was last deployed 6 hours ago, including 5 changes by 3 people.In the last week there were 74 deploys of 447 changes by 22 people.” – http://code.flickr.com/”Every engineer at Etsy writes automated tests on a daily basis, and our Hudson continuous integration server runs about 2500 tests with every code push. Since we push code around 20 times a day, that means running around 250,000 PHPUnit tests in a typical work week!” – http://codeascraft.etsy.com/

Latent Code PatternsFeature Flags (or Feature Bits, Feature Flippers, Buckets, …)

Latent Code PatternsFeature Flags (or Feature Bits, Feature Flippers, Buckets, …)<?php// …if ($cfg->enable_unicorn_polo) { // do something new and amazing here.}else { // do the current boring stuff.}// … http://code.flickr.com/blog/2009/12/02/flipping-out/

Latent Code PatternsFeature Flags (or Feature Bits, Feature Flippers, Buckets, …)<?php if (in_arrayi($this->current_user->username, Comment_Model::$bucket_like)): ?>// some fancy magic here<?php endif; ?> http://blog.forrst.com/post/782356699/how-we-deploy-new-features-on-forrst

Latent Code PatternsFeature Flags (or Feature Bits, Feature Flippers, Buckets, …)Further reading  http://code.flickr.com/blog/2009/12/02/flipping-out/  http://github.com/blog/677-how-we-deploy-new-features  http://blog.forrst.com/post/782356699/how-we-deploy-new-features-on-forrst  http://www.infoq.com/presentations/Feature-Bits

Latent Code PatternsDark Launching

Latent Code PatternsDark LaunchingFurther reading http://www.facebook.com/note.php?note_id=96390263919

Latent Code PatternsThe Nuclear Option

DevOps http://en.wikipedia.org/wiki/File:Devops.png

Why are we doing this again?We need to be able to change the application  as fast as needed to meet business requirements  and in such a way that the cost of the change does not exceed the business value of the change

Tradable Quality Hypothesishttp://martinfowler.com/bliki/TradableQualityHypothesis.html  By ”saving” on internal quality we do not gain in the other dimensions of cost, scope, or speed. Internal quality is an enabler of speed. Reducing internal quality slows us down.

The End Web: http://thePHP.cc/ http://sebastian-bergmann.de/ Mail: sebastian@thePHP.cc Twitter: @s_bergmann Slides: http://talks.thePHP.cc/ Vote: http://joind.in/2513

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Agility and Quality

by Sebastian Bergmann on Feb 25, 2011

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Agility and Quality — Presentation Transcript