Imbo\Image\Transformation\Compress::transform PHP Method

    public function transform(EventInterface $event)
    {
        $params = $event->getArgument('params');
        if (empty($params['level'])) {
            throw new TransformationException('Missing required parameter: level', 400);
        }
        $this->level = (int) $params['level'];
        if ($this->level < 0 || $this->level > 100) {
            throw new TransformationException('level must be between 0 and 100', 400);
        }
    }

 /**
  * @expectedException Imbo\Exception\TransformationException
  * @expectedExceptionMessage level must be between 0 and 100
  * @expectedExceptionCode 400
  */
 public function testThrowsExceptionOnInvalidLevel()
 {
     $event = $this->getMock('Imbo\\EventManager\\Event');
     $event->expects($this->once())->method('getArgument')->with('params')->will($this->returnValue(['level' => 200]));
     $this->transformation->transform($event);
 }