php - Modifying objects in returnCallback() of PHPUnit Mocks

Question

I want to mock a method of a class and execute a callback which modifies the object given as parameter (using PHP 5.3 with PHPUnit 3.5.5).

Let′s say I have the following class:

class A
{
  function foobar($object) 
  {
    doSomething();
  }
}

And this setup code:

$mock = $this->getMockBuilder('A')->getMock();
$mock->expects($this->any())->method('foobar')->will(
  $this->returnCallback(function($object) {
    $object->property = something;
  }));

For some reason the object does not get modified. On var_dumping $object I see it is the right object. Could it be that the object gets passed by value? How can I configure the mock to receive a reference?

Answer 1

He Alex,

i talked to Sebastian (the phpunit creator) about that problem and yes: The argument gets cloneed before it is passed to the callback.

From the top of my head i can't offer you any workaround but i choose to answer anyway to at least tell you that you are doing nothing wrong and that this is expected behavior.

To quote Sebastians comment on IRC on why it clones the argument:

It's a long-going debate between me, myself, and users of PHPUnit whether or not this is right ;-)

To have something copy/pasteable:

Assertion 3 in this codesample will fail. (The variable is only changed in the returned object)

<?php
class A
{
    function foobar($o)
    {
        $o->x = mt_rand(5, 100);
    }
}

class Test extends PHPUnit_Framework_TestCase
{
    public function testFoo()
    {
        $mock = $this->getMock('A');
        $mock->expects($this->any())
             ->method('foobar')
             ->will($this->returnCallback(function($o) { $o->x = 2; return $o; }));

        $o = new StdClass;
        $o->x = 1;

        $this->assertEquals(1, $o->x);
        $return = $mock->foobar($o);

        $this->assertEquals(2, $return->x);
        $this->assertEquals(2, $o->x);
    }
}

---

Update:

Starting with PHPUnit 3.7 the cloning can be turned off. See the last argument off:

public function getMock(
    $originalClassName, 
    $methods = array(), 
    array $arguments = array(), 
    $mockClassName = '', 
    $callOriginalConstructor = TRUE, 
    $callOriginalClone = TRUE, 
    $callAutoload = TRUE, 
    $cloneArguments = FALSE
);

It might even be off by default :)