The Bakery Everything CakePHP

Preface

Please start by reading
http://bakery.cakephp.org/articles/view/testing-models-with-cakephp-1-2-test-suite
to get the general idea of CakePHP testing, fixtures and running tests.

In this tutorial we will use a component called TransporterComponent, which uses a model called Transporter to provide functionality for other controllers. We will use four files:

• A component called Transporters found in app/controllers/components/transporter.php
• A model called Transporter found in app/models/transporter.php
• A fixture called TransporterTestFixture found in app/tests/fixtures/transporter_test_fixture.php
• The testing code, several classes, found in app/tests/cases/transporter.test.php(the dot between transporter and test is apparently important)

Preparing the component

To be able to use a component in a test we first need to tell Cake which one we intend to use. This is done by typing:
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App::import('Component', 'Transporter');


Preparing data

If our component needs access to a model, we need to prepare the data for that model using fixtures, as mentioned in the tutorial linked above.
We prepare a model for testing usage following the same pattern as the previous tutorial suggested:
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App::import('Model', 'Transporter');
class TransporterTest extends Transporter {
    var $name ='Transporter';
    var $useDbConfig = 'test_suite';
}

Notice that we did not name the model TransporterTest, since we would then have to change the component in an unfortunate way.

Initializing the component

Since CakePHP discourages from importing models directly into components (see http://manual.cakephp.org/chapter/components) we need a controller to access the data in the model.

If the startup() function of the component looks like this:
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public function startup(&$controller){
    $this->Transporter = $controller->Transporter; 
}

then we can just design a really simple fake class:
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class FakeTransporterController {}

and assign values into it like this:
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$this->TransporterComponentTest = new TransporterComponent();
$controller = new FakeTransporterController();
$controller->Transporter = new TransporterTest();
$this->TransporterComponentTest->startup(&$controller);


Writing the tests

We start with an empty test class that ensures that the fixture is loaded:
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class TransporterTestCase extends CakeTestCase {
    var $fixtures = array('transporter_test');
}

We can then add as many test functions as we want to that class. We probably need to initialize the component in each test function, so a sample test function would look something like this:
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function testGetTransporter() {
    $this->TransporterComponentTest = new TransporterComponent();
    $controller = new FakeTransporterController();
    $controller->Transporter = new TransporterTest();
    $this->TransporterComponentTest->startup(&$controller);

    $result = $this->TransporterComponentTest->getTransporter("12345", "Sweden", "54321", "Sweden");
    $this->assertEqual($result, 1, "SP is best for 1xxxx-5xxxx");
    
    $result = $this->TransporterComponentTest->getTransporter("41234", "Sweden", "44321", "Sweden");
    $this->assertEqual($result, 2, "WSTS is best for 41xxx-44xxx");

    $result = $this->TransporterComponentTest->getTransporter("41001", "Sweden", "41870", "Sweden");
    $this->assertEqual($result, 3, "GL is best for 410xx-419xx");

    $result = $this->TransporterComponentTest->getTransporter("12345", "Sweden", "54321", "Norway");
    $this->assertEqual($result, 0, "Noone can service Norway");        
}

The syntax for the different assert functions can be found in the SimpleTest documentation.

Executing the tests

Just browse to /your/cake/folder/test.php and click App Test Cases and click componentstransporter.test.php

Disclaimer

I'm a beginner PHP programmer, I have one week of CakePHP experience, no SimpleTest experience. Actually I don't have very much experience at all :)
Please comment any and all mistakes and areas of improvement that you can identify! Thanks!