PHPUnit & Continuous Integration: An Introduction

PHPUnit & Continuous Integration: An Introduction

• 1.
  PHPUnit & Continuous Integration An Introduction Friday, 16 October 2009
• 2.
  PHPUnit & CI • What is Unit Testing? • Best Practices • Why Unit Test? • Automated Test Runs • How to test • Continuous Integration • Using PHPUnit • More features of CI • Organising Tests • Advanced PHPUnit Friday, 16 October 2009
• 3.
  What is UnitTesting? • In computer programming, Unit Testing is a software verification and validation method in which a programmer tests if individual units of source code are fit for use. (Wikipedia) • A “unit” is the smallest testable part of an application: a function or class method. Friday, 16 October 2009
• 4.
  Why not UnitTest? • Writing tests is boring! • Writing tests makes development take longer • My code is perfect and has no bugs Friday, 16 October 2009
• 5.
  Why Unit Test? • You can’t prove that a program is bug free • Reduces the cost of changes; proves software still works as expected after changes have been made. • Takes pressure off Friday, 16 October 2009
• 6.
  How To Test • Tests should be repeatable, audited and isolated. • Repeatable: easy to run multiple times • Audited: results should be collated and displayed • Isolated: one test should not affect other tests and should only test one thing Friday, 16 October 2009
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  Why PHPUnit? • Makes it easy to run • Integrates with tests in a repeatable, Continuous Integration audited and isolated tools fashion. • Advanced features like: • Complete port of JUnit Mock Objects, Database 3.8 testing, class skeleton generation, Selenium • Support integrated into Eclipse, NetBeans & • Alternative: SimpleTest other IDEs Friday, 16 October 2009
• 8.
  Assertions • assertArrayHasKey • assertGreaterThan • assertClassHasAttribute • assertLessThan • assertContains • assertNotNull • assertFalse • assertRegExp • assertFileEquals • assertSame • assertFileExists • and many more! Friday, 16 October 2009
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  A Basic Example • Test case classes have a “Test” suffix • Test methods are prefixed “test” Friday, 16 October 2009
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  Running Tests • Tests can be run via: • Command Line • IDE • Continuous Integration Friday, 16 October 2009
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  Fixtures • Each test may require common operations to set up the environment • Environment should be returned to previous state after the test • Duplicating code is bad • Solution: setUp( ) and tearDown( ) Friday, 16 October 2009
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  Fixture Example • Database connection and test object instantiation are now done in setUp( ) • Database connection is closed in tearDown( ) • Connection reuse could pollute tests! Friday, 16 October 2009
• 13.
  Test Organisation • PHPUnit allows your to organise your tests into “Suites” • Suites can include other suites • Allows you to test everything in one go Friday, 16 October 2009
• 14.
  Advanced Usage • Mock Objects & Stubs • Database Testing • Skeleton Generation • Selenium • Code Coverage Friday, 16 October 2009
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  Mock Objects &Stubs • Mock objects are used as stand ins for genuine objects • Stubs are replacements for real functions that accept the same input but return a known quantity • Tests should not be dependant on code not being tested, so we use mock objects and stubs to replace them Friday, 16 October 2009
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  Database Testing • Put database into a known state before test is run • Using assertDataSetsEqual( ), the contents of a database tested • Data sets can be filtered to remove columns such as date, time • Testing multiple DBs is hard, but possible Friday, 16 October 2009
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  Skeleton Generation • PHPUnit is able to generate a class skeleton based on a test case • PHPUnit is also able to do the reverse, generate a test case skeleton based on a class Friday, 16 October 2009
• 18.
  Selenium • Selenium performs end user testing of web applications on any platform in any browser • Allows you to test that a web application is working as expected • Technically this is not unit testing, but acceptance testing Friday, 16 October 2009
• 19.
  Code Coverage • Requires Xdebug so PHPUnit can inspect what code is running • Tells you how much of your code is being tested • Helps to identify areas in need of testing or new tests that need of testing Friday, 16 October 2009
• 20.
  Best Practices • Write testable code • No globals • Don’t create objects in constructors • Don’t test private methods. Unit testing tests the interface, not the implementation. • Exploit dependencies between tests with @depends Friday, 16 October 2009
• 21.
  Automating Unit Tests • Create a cron job to run tests • Subversion pre-commit hook • Subversion post-commit hook Friday, 16 October 2009
• 22.
  Continuous Integration • Can automate the running of unit tests • More developers = more divergence • The longer you go between integrating work, the harder it is • Continuous Integration constantly integrates work • Problems are exposed quickly Friday, 16 October 2009
• 23.
  What Else CanCI Do? • Generate Documentation • Check Code Against Coding Standards • Generate Metrics • Code Coverage • Project Mess Detection Friday, 16 October 2009
• 24.
  Continuous Integration for PHP • Atlassian Bamboo • CruiseControl • phpUnderControl Friday, 16 October 2009
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  phpUnderControl • Available through PEAR on phpunit channel • Uses Subversion, PHPUnit, Xdebug, PHP_CodeSniffer, PHPDocumentor • build.xml defines what phpUnderControl will do in the build process Friday, 16 October 2009
• 26.
  Summary • Unit Testing: What it is and why we do it • PHPUnit: How to Unit Test • Continuous Integration: How it helps us create high quality code Friday, 16 October 2009
• 27.
  More Information • http://www.phpunit.de • http://phpundercontrol.org/ • Just ask! Friday, 16 October 2009