public function getMediaTypeReturnsMediaTypeBasedOnFileExtension()
{
$resource = new PersistentResource();
$resource->setFilename('file.jpg');
$this->assertSame('image/jpeg', $resource->getMediaType());
$resource = new PersistentResource();
$resource->setFilename('file.zip');
$this->assertSame('application/zip', $resource->getMediaType());
$resource = new PersistentResource();
$resource->setFilename('file.someunknownextension');
$this->assertSame('application/octet-stream', $resource->getMediaType());
}