pyo3/tests/test_class_attributes.rs

#![cfg(feature = "macros")]

use pyo3::prelude::*;

#[path = "../src/tests/common.rs"]
mod common;

#[pyclass]
struct Foo {
    #[pyo3(get)]
    x: i32,
}

#[pyclass]
struct Bar {
    #[pyo3(get)]
    x: i32,
}

#[pymethods]
impl Foo {
    #[classattr]
    const MY_CONST: &'static str = "foobar";

    #[classattr]
    #[pyo3(name = "RENAMED_CONST")]
    const MY_CONST_2: &'static str = "foobar_2";

    #[classattr]
    fn a() -> i32 {
        5
    }

    #[classattr]
    #[pyo3(name = "B")]
    fn b() -> String {
        "bar".to_string()
    }

    #[classattr]
    fn bar() -> Bar {
        Bar { x: 2 }
    }

    #[classattr]
    fn a_foo() -> Foo {
        Foo { x: 1 }
    }

    #[classattr]
    fn a_foo_with_py(py: Python<'_>) -> Py<Foo> {
        Py::new(py, Foo { x: 1 }).unwrap()
    }
}

#[test]
fn class_attributes() {
    Python::with_gil(|py| {
        let foo_obj = py.get_type::<Foo>();
        py_assert!(py, foo_obj, "foo_obj.MY_CONST == 'foobar'");
        py_assert!(py, foo_obj, "foo_obj.RENAMED_CONST == 'foobar_2'");
        py_assert!(py, foo_obj, "foo_obj.a == 5");
        py_assert!(py, foo_obj, "foo_obj.B == 'bar'");
        py_assert!(py, foo_obj, "foo_obj.a_foo.x == 1");
        py_assert!(py, foo_obj, "foo_obj.a_foo_with_py.x == 1");
    });
}

// Ignored because heap types are not immutable:
// https://github.com/python/cpython/blob/master/Objects/typeobject.c#L3399-L3409
#[test]
#[ignore]
fn class_attributes_are_immutable() {
    Python::with_gil(|py| {
        let foo_obj = py.get_type::<Foo>();
        py_expect_exception!(py, foo_obj, "foo_obj.a = 6", PyTypeError);
    });
}

#[pymethods]
impl Bar {
    #[classattr]
    fn a_foo() -> Foo {
        Foo { x: 3 }
    }
}

#[test]
fn recursive_class_attributes() {
    Python::with_gil(|py| {
        let foo_obj = py.get_type::<Foo>();
        let bar_obj = py.get_type::<Bar>();
        py_assert!(py, foo_obj, "foo_obj.a_foo.x == 1");
        py_assert!(py, foo_obj, "foo_obj.bar.x == 2");
        py_assert!(py, bar_obj, "bar_obj.a_foo.x == 3");
    });
}

#[test]
fn test_fallible_class_attribute() {
    use pyo3::{exceptions::PyValueError, types::PyString};

    struct CaptureStdErr<'py> {
        oldstderr: Bound<'py, PyAny>,
        string_io: Bound<'py, PyAny>,
    }

    impl<'py> CaptureStdErr<'py> {
        fn new(py: Python<'py>) -> PyResult<Self> {
            let sys = py.import_bound("sys")?;
            let oldstderr = sys.getattr("stderr")?;
            let string_io = py.import_bound("io")?.getattr("StringIO")?.call0()?;
            sys.setattr("stderr", &string_io)?;
            Ok(Self {
                oldstderr,
                string_io,
            })
        }

        fn reset(self) -> PyResult<String> {
            let py = self.string_io.py();
            let payload = self
                .string_io
                .getattr("getvalue")?
                .call0()?
                .downcast::<PyString>()?
                .to_cow()?
                .into_owned();
            let sys = py.import_bound("sys")?;
            sys.setattr("stderr", self.oldstderr)?;
            Ok(payload)
        }
    }

    #[pyclass]
    struct BrokenClass;

    #[pymethods]
    impl BrokenClass {
        #[classattr]
        fn fails_to_init() -> PyResult<i32> {
            Err(PyValueError::new_err("failed to create class attribute"))
        }
    }

    Python::with_gil(|py| {
        let stderr = CaptureStdErr::new(py).unwrap();
        assert!(std::panic::catch_unwind(|| py.get_type::<BrokenClass>()).is_err());
        assert_eq!(
            stderr.reset().unwrap().trim(),
            "\
ValueError: failed to create class attribute

The above exception was the direct cause of the following exception:

RuntimeError: An error occurred while initializing `BrokenClass.fails_to_init`

The above exception was the direct cause of the following exception:

RuntimeError: An error occurred while initializing class BrokenClass"
        )
    });
}

#[pyclass(get_all, set_all, rename_all = "camelCase")]
struct StructWithRenamedFields {
    first_field: bool,
    second_field: u8,
    #[pyo3(name = "third_field")]
    fourth_field: bool,
}

#[pymethods]
impl StructWithRenamedFields {
    #[new]
    fn new() -> Self {
        Self {
            first_field: true,
            second_field: 5,
            fourth_field: false,
        }
    }
}

#[test]
fn test_renaming_all_struct_fields() {
    use pyo3::types::PyBool;

    Python::with_gil(|py| {
        let struct_class = py.get_type::<StructWithRenamedFields>();
        let struct_obj = struct_class.call0().unwrap();
        assert!(struct_obj
            .setattr("firstField", PyBool::new_bound(py, false))
            .is_ok());
        py_assert!(py, struct_obj, "struct_obj.firstField == False");
        py_assert!(py, struct_obj, "struct_obj.secondField == 5");
        assert!(struct_obj
            .setattr("third_field", PyBool::new_bound(py, true))
            .is_ok());
        py_assert!(py, struct_obj, "struct_obj.third_field == True");
    });
}

macro_rules! test_case {
    ($struct_name: ident, $rule: literal, $field_name: ident, $renamed_field_name: literal, $test_name: ident) => {
        #[pyclass(get_all, set_all, rename_all = $rule)]
        #[allow(non_snake_case)]
        struct $struct_name {
            $field_name: u8,
        }
        #[pymethods]
        impl $struct_name {
            #[new]
            fn new() -> Self {
                Self { $field_name: 0 }
            }
        }
        #[test]
        fn $test_name() {
            //use pyo3::types::PyInt;

            Python::with_gil(|py| {
                let struct_class = py.get_type::<$struct_name>();
                let struct_obj = struct_class.call0().unwrap();
                assert!(struct_obj.setattr($renamed_field_name, 2).is_ok());
                let attr = struct_obj.getattr($renamed_field_name).unwrap();
                assert_eq!(2, PyAny::extract::<u8>(attr).unwrap());
            });
        }
    };
}

test_case!(
    LowercaseTest,
    "lowercase",
    fieldOne,
    "fieldone",
    test_rename_all_lowercase
);
test_case!(
    CamelCaseTest,
    "camelCase",
    field_one,
    "fieldOne",
    test_rename_all_camel_case
);
test_case!(
    KebabCaseTest,
    "kebab-case",
    field_one,
    "field-one",
    test_rename_all_kebab_case
);
test_case!(
    PascalCaseTest,
    "PascalCase",
    field_one,
    "FieldOne",
    test_rename_all_pascal_case
);
test_case!(
    ScreamingSnakeCaseTest,
    "SCREAMING_SNAKE_CASE",
    field_one,
    "FIELD_ONE",
    test_rename_all_screaming_snake_case
);
test_case!(
    ScreamingKebabCaseTest,
    "SCREAMING-KEBAB-CASE",
    field_one,
    "FIELD-ONE",
    test_rename_all_screaming_kebab_case
);
test_case!(
    SnakeCaseTest,
    "snake_case",
    fieldOne,
    "field_one",
    test_rename_all_snake_case
);
test_case!(
    UppercaseTest,
    "UPPERCASE",
    fieldOne,
    "FIELDONE",
    test_rename_all_uppercase
);