public function testSleepIncrementationOfAllIncrementables()
{
$value1 = new FixedValueFunction(1);
$value2 = new FixedValueFunction(2);
$sleep = new SleepFunction([$value1, $value2]);
call_user_func($sleep->getCallable(), 1);
$this->assertEquals(2, call_user_func($value1->getCallable()));
$this->assertEquals(3, call_user_func($value2->getCallable()));
}