PHPUnit Parameter Validation using Callback (phpunit 4.1.0)

phpunit_parameter_validation_callback.php

<?php
// Validation Callback
$validator1 = new \PHPUnit_Framework_Constraint_Callback(
    function (/** @todo add parameter **/) {
        // @todo add assertions here
        return true;
    }
);

$validator2 = new \PHPUnit_Framework_Constraint_Callback(
    function (/** @todo add parameter **/) {
        // @todo add assertions here
        return true;
    }
);

// 
$this->mock->expects($this->once())->method('$METHODNAME')->with($validator1, $validator2);