Clinner\Command\Tests\CallbackTest::testSetCallback PHP Method

    public function testSetCallback()
    {
        $closure1 = function () {
        };
        $closure2 = function ($a) {
            echo $a;
        };
        $callback = new Callback($closure1);
        $callback->setCallback($closure2);
        $this->assertAttributeSame($closure2, '_callback', $callback);
    }