def METHOD_NAME(self, m):
    m.return_value = {
        "ds": {
            "variables": {
                "k": {},
                "key": {
                    "equation": "1+1",
                },
            }
        }
    }
    result = DatasetConfig("ds").calculated_variables
    assert len(result) == 1
    assert "key" in result
    assert result["key"]["equation"] == "1+1"