PHPUnit Mock Objects and Static Methods

There is now the AspectMock library to help with this:

https://github.com/Codeception/AspectMock

$this->assertEquals('users', UserModel::tableName());   
$userModel = test::double('UserModel', ['tableName' => 'my_users']);
$this->assertEquals('my_users', UserModel::tableName());
$userModel->verifyInvoked('tableName'); 

I would make a new class in the unit test namespace that extends the Model_User and test that. Here's an example:

Original class:

class Model_User extends Doctrine_Record
{
    public static function create($userData)
    {
        $newUser = new self();
        $newUser->fromArray($userData);
        $newUser->save();
    }
}

Mock Class to call in unit test(s):

use \Model_User
class Mock_Model_User extends Model_User
{
    /** \PHPUnit\Framework\TestCase */
    public static $test;

    // This class inherits all the original classes functions.
    // However, you can override the methods and use the $test property
    // to perform some assertions.
}

In your unit test:

use Module_User;
use PHPUnit\Framework\TestCase;

class Model_UserTest extends TestCase
{
    function testCanInitialize()
    {   
        $userDataFixture = []; // Made an assumption user data would be an array.
        $sut = new Mock_Model_User::create($userDataFixture); // calls the parent ::create method, so the real thing.

        $sut::test = $this; // This is just here to show possibilities.

        $this->assertInstanceOf(Model_User::class, $sut);
    }
}

Sebastian Bergmann, the author of PHPUnit, recently had a blog post about Stubbing and Mocking Static Methods. With PHPUnit 3.5 and PHP 5.3 as well as consistent use of late static binding, you can do

$class::staticExpects($this->any())
      ->method('helper')
      ->will($this->returnValue('bar'));

Update: staticExpects is deprecated as of PHPUnit 3.8 and will be removed completely with later versions.