Example mocking Mage getSingleton

Mocking - Mage::getSingleton()

Code you want to test

<?php
class MyCompany_MyModule_Model_Example_Mocking
{
    public function doSomething()
    {
        /** @var MyCompany_MyModule_Model_Example $singleton */
        $singleton = Mage::getSingleton('mycompany_mymodule/example')
        $singleton->setSomething('foobar');

        return $singleton;
    }
}

Test implementation

<?php
class MyCompany_MyModule_Unit_Model_Example_MockingTest
    extends TechDivision_MagentoUnitTesting_TestCase_Model
{
    /**
     * @var string
     */
    protected $_testClassName = 'MyCompany_MyModule_Model_Example_Mocking';

    /**
     * @var MyCompany_MyModule_Model_Example_Mocking
     */
    protected $_instance;

    public function testDoSomething()
    {
        // Build a mock object and register it for the
        // Mage::getSingleton() method with the correct key
        $singleton = $this->buildMock('MyCompany_MyModule_Model_Example');
        $this->addMageSingleton('mycompany_mymodule/example', $singleton);

        // Method 'setSomething' must be invoked one time
        $singleton->expects($this->once())
            ->method('setSomething');

        // Method should return the singleton
        $result = $this->_instance->doSomething();
        $this->assertSame($singleton, $result);
    }
}