Cloning object in returnValue using a PHPUnit Mock

Question

I am mocking a method from a class that looks like this:

class Employee { 

/**
 * @return \DateTime
 */
public function getEmploymentBegin()
{
    return clone $this->employmentBegin;
}

My mock looks like:

$employee = $this->getMockBuilder('\MyApp\Employee')->disableOriginalConstructor()->getMock();

$employee
        ->expects($this->any())
        ->method('getEmploymentBegin')
        ->will($this->returnValue(date_create('05.11.2012')));

Later the code that I am testing needs to manipulate the date:

$a= $this->employee->getEmploymentBegin();
$b = $this->employee->getEmploymentBegin();
$b->modify('+ 6 weeks')->modify('yesterday');

My issue is that at the end Both $a and $b end-up with the same reference.

Answer 1

It looks like using returnCallback() did the job.

    $employee
        ->expects($this->any())
        ->method('getEmploymentBegin')
        ->will($this->returnCallback(
            function () { return date_create('05.11.2012'); }
        ));

Answer 2

You can change your mock to:

$date = date_create('05.11.2012');
$employee
    ->expects($this->any())
    ->method('getEmploymentBegin')
    ->will($this->onConsecutiveCalls(clone $date, clone $date));

---

The clone seems like an important implementation detail. I'm not sure how to deal with that. Maybe getEmploymentBegin should return a simple type (like a string). Anything that wants to do date arithmetic can then upgrade it to a Date.