pyo3/tests/test_class_conversion.rs

use pyo3::prelude::*;

#[pyclass]
#[derive(Clone, Debug, PartialEq)]
struct Cloneable {
    x: i32,
}

#[test]
fn test_cloneable_pyclass() {
    let c = Cloneable { x: 10 };

    let gil = Python::acquire_gil();
    let py = gil.python();

    let py_c = Py::new(py, c.clone()).unwrap().to_object(py);

    let c2: Cloneable = py_c.extract(py).unwrap();
    assert_eq!(c, c2);
    {
        let rc: PyRef<Cloneable> = py_c.extract(py).unwrap();
        assert_eq!(&c, &*rc);
        // Drops PyRef before taking PyRefMut
    }
    let mrc: PyRefMut<Cloneable> = py_c.extract(py).unwrap();
    assert_eq!(&c, &*mrc);
}