Adding a method to PhpUnits TestCase to get any method from another class and return a closure that will call it with the provided arguments

TestCase.php

<?php

abstract class TestCase extends \PHPUnit_Framework_TestCase
{

    /**
     * Gets returns a proxy for any method of an object, regardless of scope
     * @param object $object Any object
     * @param string $methodName The name of the method you want to proxy
     * @return \Closure
     */
    protected function getObjectMethod($object, $methodName)
    {
        if (!is_object($object)) {
            throw new \InvalidArgumentException('Can not get method of non object');
        }

        $reflectionMethod = new \ReflectionMethod($object, $methodName);
        $reflectionMethod->setAccessible(true);

        return function () use ($object, $reflectionMethod) {
            return $reflectionMethod->invokeArgs($object, func_get_args());
        };
    }
}