PHPUnit Testing Object-Oriented PHP Applications

Who I Am Computer-Science Student in Bonn, Germany. Member of the PHP Development Team. Author of Open Source projects like PHPUnit or phpOpenTracker.

Computer-Science Student in Bonn, Germany.

Member of the PHP Development Team.

Author of Open Source projects like PHPUnit or phpOpenTracker.

Who Are You? Who has heard of Unit Tests before? Who has used a Unit Testing framework before? Who tests software at all?

Who has heard of Unit Tests before?

Who has used a Unit Testing framework before?

Who tests software at all?

Why Unit Tests? Why Unit Tests? Why test software at all? "I have no time to write tests!" "Testing is boring and stupid!" "My code is flawless, at least it is good enough!" "It is the testing department's job to test, right?" These "excuses" lead to a vicious circle that is hard to break.

Why Unit Tests?

Why test software at all?

"I have no time to write tests!"

"Testing is boring and stupid!"

"My code is flawless, at least it is good enough!"

"It is the testing department's job to test, right?"

These "excuses" lead to a vicious circle that is hard to break.

The Benefit of Unit Tests "The fewer tests you write, the less productive you are and the less stable your code becomes. The less productive and accurate you are, the more pressure you feel. You would see the value of the immediate feedback you get from writing and saving and rerunning your own unit tests." Erich Gamma

"The fewer tests you write, the less productive you are and the less stable your code becomes.

The less productive and accurate you are, the more pressure you feel.

You would see the value of the immediate feedback you get from writing and saving and rerunning your own unit tests."

The Test-First Approach Write the test before the production code! The test motivates the production code. There can be no production code that is not covered by a test at any time. Improved confidence in the code. Write only as much production code as needed to make the previously written test pass! The production code is ready when the test passes.

Write the test before the production code!

The test motivates the production code.

There can be no production code that is not covered by a test at any time.

Improved confidence in the code.

Write only as much production code as needed to make the previously written test pass!

The production code is ready when the test passes.

Refactoring "Refactoring is a controlled technique for improving the design of an existing code base. Its essence is applying a series of small behavior-preserving transformations, each of which "too small to be worth doing". However the cumulative effect of each of these transformations is quite significant. By doing them in small steps you reduce the risk of introducing errors. You also avoid having the system broken while you are carrying out the restructuring. This allows you to gradually refactor a system over an extended period of time." Martin Fowler

"Refactoring is a controlled technique for improving the design of an existing code base.

Its essence is applying a series of small behavior-preserving transformations, each of which "too small to be worth doing".

However the cumulative effect of each of these transformations is quite significant.

By doing them in small steps you reduce the risk of introducing errors.

You also avoid having the system broken while you are carrying out the restructuring.

This allows you to gradually refactor a system over an extended period of time."

Refactoring All Unit Tests run correctly. The code communicates its design principles. The code contains no redundancies. The code contains the minimal number of classes and methods.

All Unit Tests run correctly.

The code communicates its design principles.

The code contains no redundancies.

The code contains the minimal number of classes and methods.

Refactoring Only automated tests make the changes needed to achieve the simplest design feasible. Without them you would have to test every method of every class manually.

Only automated tests make the changes needed to achieve the simplest design feasible.

Without them you would have to test every method of every class manually.

Unit Tests Unit Tests have their origin in procedural programming where each procedure was considered a unit. In object-oriented programming a unit may be a single method or class as well as the whole system. (Found on images.google.com)

Unit Tests have their origin in procedural programming where each procedure was considered a unit.

In object-oriented programming a unit may be a single method or class as well as the whole system.

PHPUnit PHPUnit is a regression testing framework used by the developer who implements Unit Tests in PHP. It is modelled after the de-facto standard of the Java world, JUnit. Work on PHPUnit for PHP 4 started in 2001. It is now deprecated. PHPUnit2 is a complete rewrite that uses the new object-oriented language features of PHP 5. It aims at "API similarity" with JUnit so that existing documentation can be leveraged.

PHPUnit is a regression testing framework used by the developer who implements Unit Tests in PHP.

It is modelled after the de-facto standard of the Java world, JUnit.

Work on PHPUnit for PHP 4 started in 2001. It is now deprecated.

PHPUnit2 is a complete rewrite that uses the new object-oriented language features of PHP 5.

It aims at "API similarity" with JUnit so that existing documentation can be leveraged.

Getting PHPUnit2

Installing PHPUnit2

The BankAccount Example Contract A bank account's balance ... is initially zero. ... cannot become negative. Interface getBalance() setBalance($balance) depositMoney($amount) withdrawMoney($amount)

Contract

A bank account's balance

... is initially zero.

... cannot become negative.

Interface

getBalance()

setBalance($balance)

depositMoney($amount)

withdrawMoney($amount)

The BankAccount Example

The BankAccount Example

The PHPUnit2 Package PHPUnit2_Framework_Assert PHPUnit2_Framework_AssertionFailedError PHPUnit2_Framework_ComparisonFailure PHPUnit2_Framework_Test PHPUnit2_Framework_TestCase PHPUnit2_Extensions_ExceptionTestCase PHPUnit2_Extensions_PerformanceTestCase PHPUnit2_Framework_TestSuite PHPUnit2_Framework_IncompleteTest PHPUnit2_Framework_TestFailure PHPUnit2_Framework_TestListener PHPUnit2_Framework_TestResult PHPUnit2_Extensions_Logger_Log PHPUnit2_Extensions_Logger_XML PHPUnit2_Extensions_TestDecorator PHPUnit2_Extensions_TestSetup PHPUnit2_Extensions_RepeatedTest PHPUnit2_Runner_BaseTestRunner PHPUnit2_TextUI_TestRunner (PHPUnit2_GtkUI_TestRunner) (PHPUnit2_WebUI_TestRunner) PHPUnit2_Runner_TestCollector PHPUnit2_Runner_IncludePathTestCollector PHPUnit2_Runner_SimpleTestCollector PHPUnit2_Runner_TestSuiteLoader PHPUnit2_Runner_StandardTestSuiteLoader PHPUnit2_Runner_TestRunListener

PHPUnit2_Framework_Assert

PHPUnit2_Framework_AssertionFailedError

PHPUnit2_Framework_ComparisonFailure

PHPUnit2_Framework_Test

PHPUnit2_Framework_TestCase

PHPUnit2_Extensions_ExceptionTestCase

PHPUnit2_Extensions_PerformanceTestCase

PHPUnit2_Framework_TestSuite

PHPUnit2_Framework_IncompleteTest

PHPUnit2_Framework_TestFailure

PHPUnit2_Framework_TestListener

PHPUnit2_Framework_TestResult

PHPUnit2_Extensions_Logger_Log

PHPUnit2_Extensions_Logger_XML

PHPUnit2_Extensions_TestDecorator

PHPUnit2_Extensions_TestSetup

PHPUnit2_Extensions_RepeatedTest

PHPUnit2_Runner_BaseTestRunner

PHPUnit2_TextUI_TestRunner

(PHPUnit2_GtkUI_TestRunner)

(PHPUnit2_WebUI_TestRunner)

PHPUnit2_Runner_TestCollector

PHPUnit2_Runner_IncludePathTestCollector

PHPUnit2_Runner_SimpleTestCollector

PHPUnit2_Runner_TestSuiteLoader

PHPUnit2_Runner_StandardTestSuiteLoader

PHPUnit2_Runner_TestRunListener

PHPUnit2_Framework_Assert Methods to be used to assert conditions in Unit Tests: assertEquals($expected, $actual, $delta = 0, $message = '') assertTrue($condition, $message = '') assertFalse($condition, $message = '') assertNotNull($object, $message = '') assertNull($object, $message = '') assertSame($expected, $actual, $message = '') assertNotSame($expected, $actual, $message = '') assertType($expected, $actual, $message = '') assertRegExp($expected, $actual, $message = '') If the expected condition cannot be asserted a PHPUnit2_ Framework_AssertionFailedError or PHPUnit2_ Framework_ComparisonFailure exception is thrown and the Unit Test results in a Failure. If another exception is thrown inside the code that is executed by the Unit Test it results in an Error. Failure != Error.

Methods to be used to assert conditions in Unit Tests:

assertEquals($expected, $actual, $delta = 0, $message = '')

assertTrue($condition, $message = '')

assertFalse($condition, $message = '')

assertNotNull($object, $message = '')

assertNull($object, $message = '')

assertSame($expected, $actual, $message = '')

assertNotSame($expected, $actual, $message = '')

assertType($expected, $actual, $message = '')

assertRegExp($expected, $actual, $message = '')

If the expected condition cannot be asserted a PHPUnit2_ Framework_AssertionFailedError or PHPUnit2_ Framework_ComparisonFailure exception is thrown and the Unit Test results in a Failure.

If another exception is thrown inside the code that is executed by the Unit Test it results in an Error.

Failure != Error.

PHPUnit2_Framework_Test Common interface to be implemented by “test classes“.

Common interface to be implemented by “test classes“.

PHPUnit2_Framework_TestCase Standard base class for Unit Tests in PHPUnit. Collects code coverage information for the Unit Test if the Xdebug extension is loaded. Can be sub-classed to change the test behaviour. PHPUnit2_Extensions_ExceptionTestCase Used to write Unit Tests that test whether or not an exception is thrown in the covered code. PHPUnit2_Extensions_PerformanceTestCase Used to write Unit Tests that track performance regressions.

Standard base class for Unit Tests in PHPUnit.

Collects code coverage information for the Unit Test if the Xdebug extension is loaded.

Can be sub-classed to change the test behaviour.

PHPUnit2_Extensions_ExceptionTestCase

Used to write Unit Tests that test whether or not an exception is thrown in the covered code.

PHPUnit2_Extensions_PerformanceTestCase

Used to write Unit Tests that track performance regressions.

PHPUnit2_Framework_TestCase Can be decorated (Decorator Pattern) to customize the test behaviour. PHPUnit2_Extensions_TestDecorator PHPUnit2_Extensions_RepeatedTest A Decorator that runs a Unit Test repeatedly. PHPUnit2_Extensions_TestSetup A Decorator to set up and tear down additional fixture state.

Can be decorated (Decorator Pattern) to customize the test behaviour.

PHPUnit2_Extensions_TestDecorator

PHPUnit2_Extensions_RepeatedTest

A Decorator that runs a Unit Test repeatedly.

PHPUnit2_Extensions_TestSetup

A Decorator to set up and tear down additional fixture state.

PHPUnit2_Framework_TestSuite A Test Suite is a composite of Unit Tests. It is used to run a collection of Unit Tests. Tests can be added dynamically / manually. $suite = new PHPUnit2_Framework_TestSuite; $suite->addTest(new FooTest('testFoo')); Tests can be added automatically. $suite = new PHPUnit2_Framework_TestSuite('FooTest'); This creates a Test Suite with all the methods of class FooTest that start with "test".

A Test Suite is a composite of Unit Tests.

It is used to run a collection of Unit Tests.

Tests can be added dynamically / manually.

$suite = new PHPUnit2_Framework_TestSuite; $suite->addTest(new FooTest('testFoo'));

Tests can be added automatically.

$suite = new PHPUnit2_Framework_TestSuite('FooTest');

This creates a Test Suite with all the methods of class FooTest that start with "test".

PHPUnit2_Framework_TestResult A Test Result collects the results of Unit Test execution. The test progress can be observed (Observer Pattern) by attaching an object of a class that implements the PHPUnit2_ Framework_TestListener interface to the Test Result object.

A Test Result collects the results of Unit Test execution.

The test progress can be observed (Observer Pattern) by attaching an object of a class that implements the PHPUnit2_ Framework_TestListener interface to the Test Result object.

PHPUnit2_Framework_TestListener

Executing Tests / Test Suites A Test or a Test Suite is executed by a Test Runner. Currently only a SAPI/CLI-based Test Runner (TextUI) is available. Invoked either from the command-line (phpunit) or by using the PHPUnit2_TextUI_TestRunner class. Both a PHP-GTK-based (GtkUI) and a Web-based (WebUI) Test Runner are planned. Demonstration!

A Test or a Test Suite is executed by a Test Runner.

Currently only a SAPI/CLI-based Test Runner (TextUI) is available.

Invoked either from the command-line (phpunit) or by using the PHPUnit2_TextUI_TestRunner class.

Both a PHP-GTK-based (GtkUI) and a Web-based (WebUI) Test Runner are planned.

Demonstration!

Last Words „ Understanding is a three-edged sword: my side, your side, and the truth.“ Do not overestimate Unit Tests. But do not underestimate them, either. Find out what works for you and helps you in writing better software. Kosh (Vorlon Ambassador to Babylon 5)

„ Understanding is a three-edged sword: my side, your side, and the truth.“

Do not overestimate Unit Tests.

But do not underestimate them, either.

Find out what works for you and helps you in writing better software.

License These slides are available under the Creative Commons Attribution-NoDerivs-NonCommercial 1.0 license. You are free to copy, distribute, display, and perform the work under the following conditions: Attribution: You must give the original author credit. Noncommercial: You may not use this work for commercial purposes. No Derivative Works: You may not alter, transform, or build upon this work. For any reuse or distribution, you must make clear to others the license terms of this work. Any of these conditions can be waived if you get permission from the author. Your fair use and other rights are in no way affected by the above.

These slides are available under the Creative Commons Attribution-NoDerivs-NonCommercial 1.0 license.

You are free to copy, distribute, display, and perform the work under the following conditions:

Attribution: You must give the original author credit.

Noncommercial: You may not use this work for commercial purposes.

No Derivative Works: You may not alter, transform, or build upon this work.

For any reuse or distribution, you must make clear to others the license terms of this work.

Any of these conditions can be waived if you get permission from the author.

Your fair use and other rights are in no way affected by the above.