In [this PR](https://github.com/localstack/localstack/pull/1200/files) we introduced a new way of starting S3 in a separate process.

In the meantime, the service startup has been significantly reworked, and it seems that we can integrate the S3 starter into the [`multiserver.py`](https://github.com/localstack/localstack/blob/master/localstack/utils/server/multiserver.py) based loading approach that loads multiple APIs in a single process, for performance reasons. We should look into that.
bucket_name = 'test-bucket-%s' % short_uid()
        self.s3_client.create_bucket(Bucket=bucket_name)
        
        for hash in ['__invalid__', '000']:
            raised = False
            try:
                self.s3_client.put_object(Bucket=bucket_name, Key='test-key',
                    Body='something', ContentMD5=hash)
            except Exception:
                raised = True
            if not raised:
                raise Exception('Invalid MD5 hash "%s" should have raised an error' % hash)
        
        self.s3_client.delete_bucket(Bucket=bucket_name)
    def test_s3_upload_download_gzip(self):