1-the-unit.php

<?php

// ...

class MyUnit
{
    private $authChecker;
    
    public function __construct(AuthorizationCheckerInterface $authChecker)
    {
        $this->authChecker = $authChecker;
    }
    
    public function someMethod()
    {
        if (!$this->authChecker->isGranted('SOME_ACTION')) {
            throw new \AccessDeniedException;
        }
        
        // ...
    }
}

2-unit-test.php

<?php

// ...

class MyUnitWithMocksTest extends \PHPUnit_Framework_TestCase
{
    /**
     * @test
     * @expectedException AccessDeniedException
     */
    public function it_avoids_X_being_done_without_proper_priveleges()
    {
        // mock the auth checker
        $authChecker = $this->prophesize(AuthorizationCheckerInterface::class);
        $authChecker->isGranted('SOME_ACTION')->will($this->returnValue(false));
        
        $subject = new MyUnit($authChecker->reveal());
        
        $subject->someMethod();
    }
}

3-functional-test.php

<?php

// ...

class MyUnitWithoutMocksTest extends \PHPUnit_Framework_TestCase
{
    /**
     * @test
     * @expectedException AccessDeniedException
     */
    public function it_avoids_X_being_done_without_proper_priveleges()
    {
        // instantiate the auth checker
        $authChecker = new AuthorizationChecker(...);
        
        $subject = new MyUnit($authChecker);
        
        $subject->someMethod();
    }
}