This document introduces PHPUnit for unit testing and continuous integration (CI). It discusses what unit testing is, why it's important, and how to set up and write tests with PHPUnit. It also covers best practices for testing and how CI can automate running tests and integrating code changes. CI helps developers work together and catch bugs early by constantly running tests on new code submissions.

1. PHPUnit &
Continuous Integration
An Introduction
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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
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3. What is Unit Testing?
• 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.
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4. Why not Unit Test?
• Writing tests is boring!
• Writing tests makes development take
longer
• My code is perfect and has no bugs
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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
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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
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7. 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
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8. Assertions
• assertArrayHasKey • assertGreaterThan
• assertClassHasAttribute • assertLessThan
• assertContains • assertNotNull
• assertFalse • assertRegExp
• assertFileEquals • assertSame
• assertFileExists • and many more!
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9. A Basic Example
• Test case classes have a “Test” suffix
• Test methods are prefixed “test”
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10. Running Tests
• Tests can be run via:
• Command Line
• IDE
• Continuous
Integration
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11. 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( )
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12. Fixture Example
• Database connection
and test object
instantiation are now
done in setUp( )
• Database connection is
closed in tearDown( )
• Connection reuse could
pollute tests!
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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
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14. Advanced Usage
• Mock Objects & Stubs
• Database Testing
• Skeleton Generation
• Selenium
• Code Coverage
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15. 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
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16. 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
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17. 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
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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
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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
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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
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21. Automating Unit Tests
• Create a cron job to run tests
• Subversion pre-commit hook
• Subversion post-commit hook
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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
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23. What Else Can CI Do?
• Generate Documentation
• Check Code Against Coding Standards
• Generate Metrics
• Code Coverage
• Project Mess Detection
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24. Continuous Integration
for PHP
• Atlassian Bamboo
• CruiseControl
• phpUnderControl
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25. 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
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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
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27. More Information
• http://www.phpunit.de
• http://phpundercontrol.org/
• Just ask!
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