'Test that reading an empty config generates no errors and that aws
credentials can be read from the environment.'

def test_empty_config(self):

    aws_key = 'testkey'
    aws_secret_key = 'testsecret'
    os.environ['AWS_ACCESS_KEY_ID'] = aws_key
    os.environ['AWS_SECRET_ACCESS_KEY'] = aws_secret_key
    tmp_file = tempfile.NamedTemporaryFile()
    cfg = config.StarClusterConfig(tmp_file.name, cache=True).load()
    assert (cfg.aws['aws_access_key_id'] == aws_key)
    assert (cfg.aws['aws_secret_access_key'] == aws_secret_key)
    del os.environ['AWS_ACCESS_KEY_ID']
    del os.environ['AWS_SECRET_ACCESS_KEY']
