How do I write unit tests in PHP? [closed]
I've read everywhere about how great they are, but for some reason I can't seem to figure out how exactly I'm supposed to test something. Could someone perhaps post a piece of example code and how they would test it? If it's not too much trouble :)
There is a 3rd "framework", which is by far easier to learn - even easier than SimpleTest, it's called phpt.
A primer can be found here: http://qa.php.net/write-test.php
Edit: Just saw your request for sample code.
Let's assume you have the following function in a file called lib.php:
<?php
function foo($bar)
{
return $bar;
}
?>
Really simple and straight forward, the parameter you pass in, is returned. So let's look at a test for this function, we'll call the test file foo.phpt:
--TEST--
foo() function - A basic test to see if it works. :)
--FILE--
<?php
include 'lib.php'; // might need to adjust path if not in the same dir
$bar = 'Hello World';
var_dump(foo($bar));
?>
--EXPECT--
string(11) "Hello World"
In a nutshell, we provide the parameter $bar with value "Hello World" and we var_dump() the response of the function call to foo().
To run this test, use: pear run-test path/to/foo.phpt
This requires a working install of PEAR on your system, which is pretty common in most circumstances. If you need to install it, I recommend to install the latest version available. In case you need help to set it up, feel free to ask (but provide OS, etc.).
There are two frameworks you can use for unit testing. Simpletest and PHPUnit, which I prefer. Read the tutorials on how to write and run tests on the homepage of PHPUnit. It is quite easy and well described.
You can make unit testing more effective by changing your coding style to accommodate it.
I recommend browsing the Google Testing Blog, in particular the post on Writing Testable Code.
I rolled my own because i didnt have time to learn someone elses way of doing things, this took about 20 minutes to write up, 10 to adapt it for posting here.
Unittesting is very usefull to me.
this is kinda long but it explains itself and there is an example at the bottom.
/**
* Provides Assertions
**/
class Assert
{
public static function AreEqual( $a, $b )
{
if ( $a != $b )
{
throw new Exception( 'Subjects are not equal.' );
}
}
}
/**
* Provides a loggable entity with information on a test and how it executed
**/
class TestResult
{
protected $_testableInstance = null;
protected $_isSuccess = false;
public function getSuccess()
{
return $this->_isSuccess;
}
protected $_output = '';
public function getOutput()
{
return $_output;
}
public function setOutput( $value )
{
$_output = $value;
}
protected $_test = null;
public function getTest()
{
return $this->_test;
}
public function getName()
{
return $this->_test->getName();
}
public function getComment()
{
return $this->ParseComment( $this->_test->getDocComment() );
}
private function ParseComment( $comment )
{
$lines = explode( "\n", $comment );
for( $i = 0; $i < count( $lines ); $i ++ )
{
$lines[$i] = trim( $lines[ $i ] );
}
return implode( "\n", $lines );
}
protected $_exception = null;
public function getException()
{
return $this->_exception;
}
static public function CreateFailure( Testable $object, ReflectionMethod $test, Exception $exception )
{
$result = new self();
$result->_isSuccess = false;
$result->testableInstance = $object;
$result->_test = $test;
$result->_exception = $exception;
return $result;
}
static public function CreateSuccess( Testable $object, ReflectionMethod $test )
{
$result = new self();
$result->_isSuccess = true;
$result->testableInstance = $object;
$result->_test = $test;
return $result;
}
}
/**
* Provides a base class to derive tests from
**/
abstract class Testable
{
protected $test_log = array();
/**
* Logs the result of a test. keeps track of results for later inspection, Overridable to log elsewhere.
**/
protected function Log( TestResult $result )
{
$this->test_log[] = $result;
printf( "Test: %s was a %s %s\n"
,$result->getName()
,$result->getSuccess() ? 'success' : 'failure'
,$result->getSuccess() ? '' : sprintf( "\n%s (lines:%d-%d; file:%s)"
,$result->getComment()
,$result->getTest()->getStartLine()
,$result->getTest()->getEndLine()
,$result->getTest()->getFileName()
)
);
}
final public function RunTests()
{
$class = new ReflectionClass( $this );
foreach( $class->GetMethods() as $method )
{
$methodname = $method->getName();
if ( strlen( $methodname ) > 4 && substr( $methodname, 0, 4 ) == 'Test' )
{
ob_start();
try
{
$this->$methodname();
$result = TestResult::CreateSuccess( $this, $method );
}
catch( Exception $ex )
{
$result = TestResult::CreateFailure( $this, $method, $ex );
}
$output = ob_get_clean();
$result->setOutput( $output );
$this->Log( $result );
}
}
}
}
/**
* a simple Test suite with two tests
**/
class MyTest extends Testable
{
/**
* This test is designed to fail
**/
public function TestOne()
{
Assert::AreEqual( 1, 2 );
}
/**
* This test is designed to succeed
**/
public function TestTwo()
{
Assert::AreEqual( 1, 1 );
}
}
// this is how to use it.
$test = new MyTest();
$test->RunTests();
This outputs:
Test: TestOne was a failure /** * This test is designed to fail **/ (lines:149-152; file:/Users/kris/Desktop/Testable.php) Test: TestTwo was a success
Get PHPUnit. It is very easy to use.
Then start with very simple assertions. You can do alot with AssertEquals before you get into anything else. That's a good way to get your feet wet.
You may also want to try writing your test first (since you gave your question the TDD tag) and then write your code. If you haven't done this before it is an eye-opener.
require_once 'ClassYouWantToTest';
require_once 'PHPUnit...blah,blah,whatever';
class ClassYouWantToTest extends PHPUnit...blah,blah,whatever
{
private $ClassYouWantToTest;
protected function setUp ()
{
parent::setUp();
$this->ClassYouWantToTest = new ClassYouWantToTest(/* parameters */);
}
protected function tearDown ()
{
$this->ClassYouWantToTest = null;
parent::tearDown();
}
public function __construct ()
{
// not really needed
}
/**
* Tests ClassYouWantToTest->methodFoo()
*/
public function testMethodFoo ()
{
$this->assertEquals(
$this->ClassYouWantToTest->methodFoo('putValueOfParamHere), 'expectedOutputHere);
/**
* Tests ClassYouWantToTest->methodBar()
*/
public function testMethodFoo ()
{
$this->assertEquals(
$this->ClassYouWantToTest->methodBar('putValueOfParamHere), 'expectedOutputHere);
}