PHP mockery logic class.

Temperature.php

<?php

namespace App;

class Temperature
{
    private $service;

    public function __construct($service)
    {
        $this->service = $service;
    }

    public function average()
    {
        $total = 0;
        $count = $this->service->count();

        for ($i = 0; $i < $count; $i++) {
            $total += $this->service->readTemp();
        }

        return ($total / $count);
    }
}

see TemperatureTest.php