@pytest.fixture()
def store_purge(self, **kwargs):
    if ((kwargs.get('age') == '-1') or (kwargs.get('size') == '-1')):
        raise StorageServerError(400, 'Bla', 'Some Error')
    return {'readings': 10, 'removed': 1, 'unsentPurged': 2, 'unsentRetained': 7}
@pytest.fixture()
def store_purge(self, **kwargs):
    if ((kwargs.get('age') == '-1') or (kwargs.get('size') == '-1')):
        raise StorageServerError(400, 'Bla', 'Some Error')
    return {'readings': 10, 'removed': 1, 'unsentPurged': 2, 'unsentRetained': 7}