GCSFeedStorage requires google-cloud-storage

Raise code

class GCSFeedStorageTest(unittest.TestCase):

    def test_parse_settings(self):
        try:
            from google.cloud.storage import Client  # noqa
        except ImportError:
            raise unittest.SkipTest("GCSFeedStorage requires google-cloud-storage")

        settings = {'GCS_PROJECT_ID': '123', 'FEED_STORAGE_GCS_ACL': 'publicRead'}
        crawler = get_crawler(settings_dict=settings)
        storage = GCSFeedStorage.from_crawler(crawler, 'gs://mybucket/export.csv')
        assert storage.project_id == '123'
        assert storage.acl == 'publicRead'
        assert storage.bucket_name == 'mybucket'