use crate::err::PyResult;
use crate::ffi_ptr_ext::FfiPtrExt;
use crate::py_result_ext::PyResultExt;
use crate::type_object::PyTypeCheck;
use crate::types::any::PyAny;
use crate::{ffi, Borrowed, Bound, ToPyObject};

#[cfg(feature = "gil-refs")]
use crate::{type_object::PyTypeInfo, PyNativeType};

use super::PyWeakrefMethods;

/// Represents any Python `weakref` Proxy type.
///
/// In Python this is created by calling `weakref.proxy`.
/// This is either a `weakref.ProxyType` or a `weakref.CallableProxyType` (`weakref.ProxyTypes`).
#[repr(transparent)]
pub struct PyWeakrefProxy(PyAny);

pyobject_native_type_named!(PyWeakrefProxy);
pyobject_native_type_extract!(PyWeakrefProxy);

// TODO: We known the layout but this cannot be implemented, due to the lack of public typeobject pointers. And it is 2 distinct types
// #[cfg(not(Py_LIMITED_API))]
// pyobject_native_type_sized!(PyWeakrefProxy, ffi::PyWeakReference);

impl PyTypeCheck for PyWeakrefProxy {
    const NAME: &'static str = "weakref.ProxyTypes";

    fn type_check(object: &Bound<'_, PyAny>) -> bool {
        unsafe { ffi::PyWeakref_CheckProxy(object.as_ptr()) > 0 }
    }
}

/// TODO: UPDATE DOCS
impl PyWeakrefProxy {
    /// Constructs a new Weak Reference (`weakref.proxy`/`weakref.ProxyType`/`weakref.CallableProxyType`) for the given object.
    ///
    /// Returns a `TypeError` if `object` is not weak referenceable (Most native types and PyClasses without `weakref` flag).
    ///
    /// # Examples
    #[cfg_attr(
        not(all(feature = "macros", not(all(Py_LIMITED_API, not(Py_3_9))))),
        doc = "```rust,ignore"
    )]
    #[cfg_attr(
        all(feature = "macros", not(all(Py_LIMITED_API, not(Py_3_9)))),
        doc = "```rust"
    )]
    /// use pyo3::prelude::*;
    /// use pyo3::types::PyWeakrefProxy;
    ///
    /// #[pyclass(weakref)]
    /// struct Foo { /* fields omitted */ }
    ///
    /// # fn main() -> PyResult<()> {
    /// Python::with_gil(|py| {
    ///     let foo = Bound::new(py, Foo {})?;
    ///     let weakref = PyWeakrefProxy::new_bound(&foo)?;
    ///     assert!(
    ///         // In normal situations where a direct `Bound<'py, Foo>` is required use `upgrade::<Foo>`
    ///         weakref.upgrade()
    ///             .map_or(false, |obj| obj.is(&foo))
    ///     );
    ///
    ///     let weakref2 = PyWeakrefProxy::new_bound(&foo)?;
    ///     assert!(weakref.is(&weakref2));
    ///
    ///     drop(foo);
    ///
    ///     assert!(weakref.upgrade().is_none());
    ///     Ok(())
    /// })
    /// # }
    /// ```
    #[inline]
    pub fn new_bound<'py>(object: &Bound<'py, PyAny>) -> PyResult<Bound<'py, PyWeakrefProxy>> {
        // TODO: Is this inner pattern still necessary Here?
        fn inner<'py>(object: &Bound<'py, PyAny>) -> PyResult<Bound<'py, PyWeakrefProxy>> {
            unsafe {
                Bound::from_owned_ptr_or_err(
                    object.py(),
                    ffi::PyWeakref_NewProxy(object.as_ptr(), ffi::Py_None()),
                )
                .downcast_into_unchecked()
            }
        }

        inner(object)
    }

    /// Constructs a new Weak Reference (`weakref.proxy`/`weakref.ProxyType`/`weakref.CallableProxyType`) for the given object with a callback.
    ///
    /// Returns a `TypeError` if `object` is not weak referenceable (Most native types and PyClasses without `weakref` flag) or if the `callback` is not callable or None.
    ///
    /// # Examples
    #[cfg_attr(
        not(all(feature = "macros", not(all(Py_LIMITED_API, not(Py_3_9))))),
        doc = "```rust,ignore"
    )]
    #[cfg_attr(
        all(feature = "macros", not(all(Py_LIMITED_API, not(Py_3_9)))),
        doc = "```rust"
    )]
    /// use pyo3::prelude::*;
    /// use pyo3::types::PyWeakrefProxy;
    ///
    /// #[pyclass(weakref)]
    /// struct Foo { /* fields omitted */ }
    ///
    /// #[pyfunction]
    /// fn callback(wref: Bound<'_, PyWeakrefProxy>) -> PyResult<()> {
    ///         let py = wref.py();
    ///         assert!(wref.upgrade_as::<Foo>()?.is_none());
    ///         py.run_bound("counter = 1", None, None)
    /// }
    ///
    /// # fn main() -> PyResult<()> {
    /// Python::with_gil(|py| {
    ///     py.run_bound("counter = 0", None, None)?;
    ///     assert_eq!(py.eval_bound("counter", None, None)?.extract::<u32>()?, 0);
    ///     let foo = Bound::new(py, Foo{})?;
    ///
    ///     // This is fine.
    ///     let weakref = PyWeakrefProxy::new_bound_with(&foo, py.None())?;
    ///     assert!(weakref.upgrade_as::<Foo>()?.is_some());
    ///     assert!(
    ///         // In normal situations where a direct `Bound<'py, Foo>` is required use `upgrade::<Foo>`
    ///         weakref.upgrade()
    ///             .map_or(false, |obj| obj.is(&foo))
    ///     );
    ///     assert_eq!(py.eval_bound("counter", None, None)?.extract::<u32>()?, 0);
    ///
    ///     let weakref2 = PyWeakrefProxy::new_bound_with(&foo, wrap_pyfunction_bound!(callback, py)?)?;
    ///     assert!(!weakref.is(&weakref2)); // Not the same weakref
    ///     assert!(weakref.eq(&weakref2)?);  // But Equal, since they point to the same object
    ///
    ///     drop(foo);
    ///
    ///     assert!(weakref.upgrade_as::<Foo>()?.is_none());
    ///     assert_eq!(py.eval_bound("counter", None, None)?.extract::<u32>()?, 1);
    ///     Ok(())
    /// })
    /// # }
    /// ```
    #[inline]
    pub fn new_bound_with<'py, C>(
        object: &Bound<'py, PyAny>,
        callback: C,
    ) -> PyResult<Bound<'py, PyWeakrefProxy>>
    where
        C: ToPyObject,
    {
        fn inner<'py>(
            object: &Bound<'py, PyAny>,
            callback: Bound<'py, PyAny>,
        ) -> PyResult<Bound<'py, PyWeakrefProxy>> {
            unsafe {
                Bound::from_owned_ptr_or_err(
                    object.py(),
                    ffi::PyWeakref_NewProxy(object.as_ptr(), callback.as_ptr()),
                )
                .downcast_into_unchecked()
            }
        }

        let py = object.py();
        inner(object, callback.to_object(py).into_bound(py))
    }
}

/// TODO: UPDATE DOCS
#[cfg(feature = "gil-refs")]
impl PyWeakrefProxy {
    /// Deprecated form of [`PyWeakrefProxy::new_bound`].
    #[inline]
    #[deprecated(
        since = "0.21.0",
        note = "`PyWeakrefProxy::new` will be replaced by `PyWeakrefProxy::new_bound` in a future PyO3 version"
    )]
    pub fn new<T>(object: &T) -> PyResult<&PyWeakrefProxy>
    where
        T: PyNativeType,
    {
        Self::new_bound(object.as_borrowed().as_any()).map(Bound::into_gil_ref)
    }

    /// Deprecated form of [`PyWeakrefProxy::new_bound_with`].
    #[inline]
    #[deprecated(
        since = "0.21.0",
        note = "`PyWeakrefProxy::new_with` will be replaced by `PyWeakrefProxy::new_bound_with` in a future PyO3 version"
    )]
    pub fn new_with<T, C>(object: &T, callback: C) -> PyResult<&PyWeakrefProxy>
    where
        T: PyNativeType,
        C: ToPyObject,
    {
        Self::new_bound_with(object.as_borrowed().as_any(), callback).map(Bound::into_gil_ref)
    }

    /// Upgrade the weakref to a direct object reference.
    ///
    /// It is named `upgrade` to be inline with [rust's `Weak::upgrade`](std::rc::Weak::upgrade).
    /// In Python it would be equivalent to [`PyWeakref_GetObject`].
    ///
    /// # Example
    #[cfg_attr(
        not(all(feature = "macros", not(all(Py_LIMITED_API, not(Py_3_9))))),
        doc = "```rust,ignore"
    )]
    #[cfg_attr(
        all(feature = "macros", not(all(Py_LIMITED_API, not(Py_3_9)))),
        doc = "```rust"
    )]
    /// use pyo3::prelude::*;
    /// use pyo3::types::PyWeakrefProxy;
    ///
    /// #[pyclass(weakref)]
    /// struct Foo { /* fields omitted */ }
    ///
    /// #[pymethods]
    /// impl Foo {
    ///     fn get_data(&self) -> (&str, u32) {
    ///         ("Dave", 10)
    ///     }
    /// }
    ///
    /// fn parse_data(reference: Borrowed<'_, '_, PyWeakrefProxy>) -> PyResult<String> {
    ///     if let Some(data_src) = reference.upgrade_as::<Foo>()? {
    ///         let data = data_src.borrow();
    ///         let (name, score) = data.get_data();
    ///         Ok(format!("Processing '{}': score = {}", name, score))
    ///     } else {
    ///         Ok("The supplied data reference is nolonger relavent.".to_owned())
    ///     }
    /// }
    ///
    /// # fn main() -> PyResult<()> {
    /// Python::with_gil(|py| {
    ///     let data = Bound::new(py, Foo{})?;
    ///     let reference = PyWeakrefProxy::new_bound(&data)?;
    ///
    ///     assert_eq!(
    ///         parse_data(reference.as_borrowed())?,
    ///         "Processing 'Dave': score = 10"
    ///     );
    ///
    ///     drop(data);
    ///
    ///     assert_eq!(
    ///         parse_data(reference.as_borrowed())?,
    ///         "The supplied data reference is nolonger relavent."
    ///     );
    ///
    ///     Ok(())
    /// })
    /// # }
    /// ```
    ///
    /// # Panics
    /// This function panics is the current object is invalid.
    /// If used propperly this is never the case. (NonNull and actually a weakref type)
    ///
    /// [`PyWeakref_GetObject`]: https://docs.python.org/3/c-api/weakref.html#c.PyWeakref_GetObject
    /// [`weakref.ProxyType`]: https://docs.python.org/3/library/weakref.html#weakref.ProxyType
    /// [`weakref.proxy`]: https://docs.python.org/3/library/weakref.html#weakref.proxy
    pub fn upgrade_as<T>(&self) -> PyResult<Option<&T::AsRefTarget>>
    where
        T: PyTypeCheck,
    {
        Ok(self
            .as_borrowed()
            .upgrade_as::<T>()?
            .map(Bound::into_gil_ref))
    }

    /// Upgrade the weakref to a direct object reference unchecked. The type of the recovered object is not checked before downcasting, this could lead to unexpected behavior. Use only when absolutely certain the type can be guaranteed. The `weakref` may still return `None`.
    ///
    /// It is named `upgrade` to be inline with [rust's `Weak::upgrade`](std::rc::Weak::upgrade).
    /// In Python it would be equivalent to [`PyWeakref_GetObject`].
    ///
    /// # Safety
    /// Callers must ensure that the type is valid or risk type confusion.
    /// The `weakref` is still allowed to be `None`, if the referenced object has been cleaned up.
    ///
    /// # Example
    #[cfg_attr(
        not(all(feature = "macros", not(all(Py_LIMITED_API, not(Py_3_9))))),
        doc = "```rust,ignore"
    )]
    #[cfg_attr(
        all(feature = "macros", not(all(Py_LIMITED_API, not(Py_3_9)))),
        doc = "```rust"
    )]
    /// use pyo3::prelude::*;
    /// use pyo3::types::PyWeakrefProxy;
    ///
    /// #[pyclass(weakref)]
    /// struct Foo { /* fields omitted */ }
    ///
    /// #[pymethods]
    /// impl Foo {
    ///     fn get_data(&self) -> (&str, u32) {
    ///         ("Dave", 10)
    ///     }
    /// }
    ///
    /// fn parse_data(reference: Borrowed<'_, '_, PyWeakrefProxy>) -> String {
    ///     if let Some(data_src) = unsafe { reference.upgrade_as_unchecked::<Foo>() } {
    ///         let data = data_src.borrow();
    ///         let (name, score) = data.get_data();
    ///         format!("Processing '{}': score = {}", name, score)
    ///     } else {
    ///         "The supplied data reference is nolonger relavent.".to_owned()
    ///     }
    /// }
    ///
    /// # fn main() -> PyResult<()> {
    /// Python::with_gil(|py| {
    ///     let data = Bound::new(py, Foo{})?;
    ///     let reference = PyWeakrefProxy::new_bound(&data)?;
    ///
    ///     assert_eq!(
    ///         parse_data(reference.as_borrowed()),
    ///         "Processing 'Dave': score = 10"
    ///     );
    ///
    ///     drop(data);
    ///
    ///     assert_eq!(
    ///         parse_data(reference.as_borrowed()),
    ///         "The supplied data reference is nolonger relavent."
    ///     );
    ///
    ///     Ok(())
    /// })
    /// # }
    /// ```
    ///
    /// # Panics
    /// This function panics is the current object is invalid.
    /// If used propperly this is never the case. (NonNull and actually a weakref type)
    ///
    /// [`PyWeakref_GetObject`]: https://docs.python.org/3/c-api/weakref.html#c.PyWeakref_GetObject
    /// [`weakref.ProxyType`]: https://docs.python.org/3/library/weakref.html#weakref.ProxyType
    /// [`weakref.proxy`]: https://docs.python.org/3/library/weakref.html#weakref.proxy
    pub unsafe fn upgrade_as_unchecked<T>(&self) -> Option<&T::AsRefTarget>
    where
        T: PyTypeCheck,
    {
        self.as_borrowed()
            .upgrade_as_unchecked::<T>()
            .map(Bound::into_gil_ref)
    }

    /// Upgrade the weakref to an exact direct object reference.
    ///
    /// It is named `upgrade` to be inline with [rust's `Weak::upgrade`](std::rc::Weak::upgrade).
    /// In Python it would be equivalent to [`PyWeakref_GetObject`].
    ///
    /// # Example
    #[cfg_attr(
        not(all(feature = "macros", not(all(Py_LIMITED_API, not(Py_3_9))))),
        doc = "```rust,ignore"
    )]
    #[cfg_attr(
        all(feature = "macros", not(all(Py_LIMITED_API, not(Py_3_9)))),
        doc = "```rust"
    )]
    /// use pyo3::prelude::*;
    /// use pyo3::types::PyWeakrefProxy;
    ///
    /// #[pyclass(weakref)]
    /// struct Foo { /* fields omitted */ }
    ///
    /// #[pymethods]
    /// impl Foo {
    ///     fn get_data(&self) -> (&str, u32) {
    ///         ("Dave", 10)
    ///     }
    /// }
    ///
    /// fn parse_data(reference: Borrowed<'_, '_, PyWeakrefProxy>) -> PyResult<String> {
    ///     if let Some(data_src) = reference.upgrade_as_exact::<Foo>()? {
    ///         let data = data_src.borrow();
    ///         let (name, score) = data.get_data();
    ///         Ok(format!("Processing '{}': score = {}", name, score))
    ///     } else {
    ///         Ok("The supplied data reference is nolonger relavent.".to_owned())
    ///     }
    /// }
    ///
    /// # fn main() -> PyResult<()> {
    /// Python::with_gil(|py| {
    ///     let data = Bound::new(py, Foo{})?;
    ///     let reference = PyWeakrefProxy::new_bound(&data)?;
    ///
    ///     assert_eq!(
    ///         parse_data(reference.as_borrowed())?,
    ///         "Processing 'Dave': score = 10"
    ///     );
    ///
    ///     drop(data);
    ///
    ///     assert_eq!(
    ///         parse_data(reference.as_borrowed())?,
    ///         "The supplied data reference is nolonger relavent."
    ///     );
    ///
    ///     Ok(())
    /// })
    /// # }
    /// ```
    ///
    /// # Panics
    /// This function panics is the current object is invalid.
    /// If used propperly this is never the case. (NonNull and actually a weakref type)
    ///
    /// [`PyWeakref_GetObject`]: https://docs.python.org/3/c-api/weakref.html#c.PyWeakref_GetObject
    /// [`weakref.ProxyType`]: https://docs.python.org/3/library/weakref.html#weakref.ProxyType
    /// [`weakref.proxy`]: https://docs.python.org/3/library/weakref.html#weakref.proxy
    pub fn upgrade_as_exact<T>(&self) -> PyResult<Option<&T::AsRefTarget>>
    where
        T: PyTypeInfo,
    {
        Ok(self
            .as_borrowed()
            .upgrade_as_exact::<T>()?
            .map(Bound::into_gil_ref))
    }

    /// Upgrade the weakref to a [`PyAny`] reference to the target if possible.
    ///
    /// It is named `upgrade` to be inline with [rust's `Weak::upgrade`](std::rc::Weak::upgrade).
    /// This function returns `Some(&'py PyAny)` if the reference still exists, otherwise `None` will be returned.
    ///
    /// This function gets the optional target of this [`weakref.ProxyType`] (or [`weakref.CallableProxyType`], result of calling [`weakref.proxy`]).
    /// It produces similair results using [`PyWeakref_GetObject`] in the C api.
    ///
    /// # Example
    #[cfg_attr(
        not(all(feature = "macros", not(all(Py_LIMITED_API, not(Py_3_9))))),
        doc = "```rust,ignore"
    )]
    #[cfg_attr(
        all(feature = "macros", not(all(Py_LIMITED_API, not(Py_3_9)))),
        doc = "```rust"
    )]
    /// use pyo3::prelude::*;
    /// use pyo3::types::PyWeakrefProxy;
    ///
    /// #[pyclass(weakref)]
    /// struct Foo { /* fields omitted */ }
    ///
    /// fn parse_data(reference: Borrowed<'_, '_, PyWeakrefProxy>) -> PyResult<String> {
    ///     if let Some(object) = reference.upgrade() {
    ///         Ok(format!("The object '{}' refered by this reference still exists.", object.getattr("__class__")?.getattr("__qualname__")?))
    ///     } else {
    ///         Ok("The object, which this reference refered to, no longer exists".to_owned())
    ///     }
    /// }
    ///
    /// # fn main() -> PyResult<()> {
    /// Python::with_gil(|py| {
    ///     let data = Bound::new(py, Foo{})?;
    ///     let reference = PyWeakrefProxy::new_bound(&data)?;
    ///
    ///     assert_eq!(
    ///         parse_data(reference.as_borrowed())?,
    ///         "The object 'Foo' refered by this reference still exists."
    ///     );
    ///
    ///     drop(data);
    ///
    ///     assert_eq!(
    ///         parse_data(reference.as_borrowed())?,
    ///         "The object, which this reference refered to, no longer exists"
    ///     );
    ///
    ///     Ok(())
    /// })
    /// # }
    /// ```
    ///
    /// # Panics
    /// This function panics is the current object is invalid.
    /// If used propperly this is never the case. (NonNull and actually a weakref type)
    ///
    /// [`PyWeakref_GetObject`]: https://docs.python.org/3/c-api/weakref.html#c.PyWeakref_GetObject
    /// [`weakref.ProxyType`]: https://docs.python.org/3/library/weakref.html#weakref.ProxyType
    /// [`weakref.CallableProxyType`]: https://docs.python.org/3/library/weakref.html#weakref.CallableProxyType
    /// [`weakref.proxy`]: https://docs.python.org/3/library/weakref.html#weakref.proxy
    pub fn upgrade(&self) -> Option<&'_ PyAny> {
        self.as_borrowed().upgrade().map(Bound::into_gil_ref)
    }

    /// Retrieve to a object pointed to by the weakref.
    ///
    /// This function returns `&'py PyAny`, which is either the object if it still exists, otherwise it will refer to [`PyNone`](crate::types::PyNone).
    ///
    /// This function gets the optional target of this [`weakref.ProxyType`] (or [`weakref.CallableProxyType`], result of calling [`weakref.proxy`]).
    /// It produces similair results using [`PyWeakref_GetObject`] in the C api.
    ///
    /// # Example
    #[cfg_attr(
        not(all(feature = "macros", not(all(Py_LIMITED_API, not(Py_3_9))))),
        doc = "```rust,ignore"
    )]
    #[cfg_attr(
        all(feature = "macros", not(all(Py_LIMITED_API, not(Py_3_9)))),
        doc = "```rust"
    )]
    /// use pyo3::prelude::*;
    /// use pyo3::types::PyWeakrefProxy;
    ///
    /// #[pyclass(weakref)]
    /// struct Foo { /* fields omitted */ }
    ///
    /// fn get_class(reference: Borrowed<'_, '_, PyWeakrefProxy>) -> PyResult<String> {
    ///     reference
    ///         .get_object()
    ///         .getattr("__class__")?
    ///         .repr()
    ///         .map(|repr| repr.to_string())
    /// }
    ///
    /// # fn main() -> PyResult<()> {
    /// Python::with_gil(|py| {
    ///     let object = Bound::new(py, Foo{})?;
    ///     let reference = PyWeakrefProxy::new_bound(&object)?;
    ///
    ///     assert_eq!(
    ///         get_class(reference.as_borrowed())?,
    ///         "<class 'builtins.Foo'>"
    ///     );
    ///
    ///     drop(object);
    ///
    ///     assert_eq!(get_class(reference.as_borrowed())?, "<class 'NoneType'>");
    ///
    ///     Ok(())
    /// })
    /// # }
    /// ```
    ///
    /// # Panics
    /// This function panics is the current object is invalid.
    /// If used propperly this is never the case. (NonNull and actually a weakref type)
    ///
    /// [`PyWeakref_GetObject`]: https://docs.python.org/3/c-api/weakref.html#c.PyWeakref_GetObject
    /// [`weakref.ProxyType`]: https://docs.python.org/3/library/weakref.html#weakref.ProxyType
    /// [`weakref.CallableProxyType`]: https://docs.python.org/3/library/weakref.html#weakref.CallableProxyType
    /// [`weakref.proxy`]: https://docs.python.org/3/library/weakref.html#weakref.proxy
    pub fn get_object(&self) -> &'_ PyAny {
        self.as_borrowed().get_object().into_gil_ref()
    }
}

impl<'py> PyWeakrefMethods<'py> for Bound<'py, PyWeakrefProxy> {
    fn get_object_borrowed(&self) -> Borrowed<'_, 'py, PyAny> {
        // PyWeakref_GetObject does some error checking, however we ensure the passed object is Non-Null and a Weakref type.
        unsafe { ffi::PyWeakref_GetObject(self.as_ptr()).assume_borrowed_or_err(self.py()) }
            .expect("The 'weakref.ProxyType' (or `weakref.CallableProxyType`) instance should be valid (non-null and actually a weakref reference)")
    }
}

#[cfg(test)]
mod tests {
    use crate::exceptions::{PyAttributeError, PyReferenceError, PyTypeError};
    use crate::types::any::{PyAny, PyAnyMethods};
    use crate::types::weakref::{PyWeakrefMethods, PyWeakrefProxy};
    use crate::{Bound, PyResult, Python};

    #[cfg(all(Py_3_13, not(Py_LIMITED_API)))]
    const DEADREF_FIX: Option<&str> = None;
    #[cfg(all(not(Py_3_13), not(Py_LIMITED_API)))]
    const DEADREF_FIX: Option<&str> = Some("NoneType");

    #[cfg(not(Py_LIMITED_API))]
    fn check_repr(
        reference: &Bound<'_, PyWeakrefProxy>,
        object: &Bound<'_, PyAny>,
        class: Option<&str>,
    ) -> PyResult<()> {
        let repr = reference.repr()?.to_string();

        #[cfg(Py_3_13)]
        let (first_part, second_part) = repr.split_once(';').unwrap();
        #[cfg(not(Py_3_13))]
        let (first_part, second_part) = repr.split_once(" to ").unwrap();

        {
            let (msg, addr) = first_part.split_once("0x").unwrap();

            assert_eq!(msg, "<weakproxy at ");
            assert!(addr
                .to_lowercase()
                .contains(format!("{:x?}", reference.as_ptr()).split_at(2).1));
        }

        if let Some(class) = class.or(DEADREF_FIX) {
            let (msg, addr) = second_part.split_once("0x").unwrap();

            // Avoids not succeeding at unreliable quotation (Python 3.13-dev adds ' around classname without documenting)
            #[cfg(Py_3_13)]
            assert!(msg.starts_with(" to '"));
            assert!(msg.contains(class));
            assert!(msg.ends_with(" at "));

            assert!(addr
                .to_lowercase()
                .contains(format!("{:x?}", object.as_ptr()).split_at(2).1));
        } else {
            assert!(second_part.contains("dead"));
        }

        Ok(())
    }

    mod proxy {
        use super::*;

        #[cfg(all(not(Py_LIMITED_API), Py_3_10))]
        const CLASS_NAME: &str = "'weakref.ProxyType'";
        #[cfg(all(not(Py_LIMITED_API), not(Py_3_10)))]
        const CLASS_NAME: &str = "'weakproxy'";

        mod python_class {
            use super::*;
            use crate::{py_result_ext::PyResultExt, types::PyType};

            fn get_type(py: Python<'_>) -> PyResult<Bound<'_, PyType>> {
                py.run_bound("class A:\n    pass\n", None, None)?;
                py.eval_bound("A", None, None).downcast_into::<PyType>()
            }

            #[test]
            fn test_weakref_proxy_behavior() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    assert!(!reference.is(&object));
                    assert!(reference.get_object().is(&object));

                    #[cfg(not(Py_LIMITED_API))]
                    assert_eq!(
                        reference.get_type().to_string(),
                        format!("<class {}>", CLASS_NAME)
                    );

                    assert_eq!(
                        reference.getattr("__class__")?.to_string(),
                        "<class '__main__.A'>"
                    );
                    #[cfg(not(Py_LIMITED_API))]
                    check_repr(&reference, &object, Some("A"))?;

                    assert!(reference
                        .getattr("__callback__")
                        .err()
                        .map_or(false, |err| err.is_instance_of::<PyAttributeError>(py)));

                    assert!(reference.call0().err().map_or(false, |err| {
                        let result = err.is_instance_of::<PyTypeError>(py);
                        #[cfg(not(Py_LIMITED_API))]
                        let result = result
                            & (err.value_bound(py).to_string()
                                == format!("{} object is not callable", CLASS_NAME));
                        result
                    }));

                    drop(object);

                    assert!(reference.get_object().is_none());
                    assert!(reference
                        .getattr("__class__")
                        .err()
                        .map_or(false, |err| err.is_instance_of::<PyReferenceError>(py)));
                    #[cfg(not(Py_LIMITED_API))]
                    check_repr(&reference, py.None().bind(py), None)?;

                    assert!(reference
                        .getattr("__callback__")
                        .err()
                        .map_or(false, |err| err.is_instance_of::<PyReferenceError>(py)));

                    assert!(reference.call0().err().map_or(false, |err| {
                        let result = err.is_instance_of::<PyTypeError>(py);
                        #[cfg(not(Py_LIMITED_API))]
                        let result = result
                            & (err.value_bound(py).to_string()
                                == format!("{} object is not callable", CLASS_NAME));
                        result
                    }));

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_as() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    {
                        // This test is a bit weird but ok.
                        let obj = reference.upgrade_as::<PyAny>();

                        assert!(obj.is_ok());
                        let obj = obj.unwrap();

                        assert!(obj.is_some());
                        assert!(obj.map_or(false, |obj| obj.as_ptr() == object.as_ptr()
                            && obj.is_exact_instance(&class)));
                    }

                    drop(object);

                    {
                        // This test is a bit weird but ok.
                        let obj = reference.upgrade_as::<PyAny>();

                        assert!(obj.is_ok());
                        let obj = obj.unwrap();

                        assert!(obj.is_none());
                    }

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_borrowed_as() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    {
                        // This test is a bit weird but ok.
                        let obj = reference.upgrade_borrowed_as::<PyAny>();

                        assert!(obj.is_ok());
                        let obj = obj.unwrap();

                        assert!(obj.is_some());
                        assert!(obj.map_or(false, |obj| obj.as_ptr() == object.as_ptr()
                            && obj.is_exact_instance(&class)));
                    }

                    drop(object);

                    {
                        // This test is a bit weird but ok.
                        let obj = reference.upgrade_borrowed_as::<PyAny>();

                        assert!(obj.is_ok());
                        let obj = obj.unwrap();

                        assert!(obj.is_none());
                    }

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_as_unchecked() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    {
                        // This test is a bit weird but ok.
                        let obj = unsafe { reference.upgrade_as_unchecked::<PyAny>() };

                        assert!(obj.is_some());
                        assert!(obj.map_or(false, |obj| obj.as_ptr() == object.as_ptr()
                            && obj.is_exact_instance(&class)));
                    }

                    drop(object);

                    {
                        // This test is a bit weird but ok.
                        let obj = unsafe { reference.upgrade_as_unchecked::<PyAny>() };

                        assert!(obj.is_none());
                    }

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_borrowed_as_unchecked() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    {
                        // This test is a bit weird but ok.
                        let obj = unsafe { reference.upgrade_borrowed_as_unchecked::<PyAny>() };

                        assert!(obj.is_some());
                        assert!(obj.map_or(false, |obj| obj.as_ptr() == object.as_ptr()
                            && obj.is_exact_instance(&class)));
                    }

                    drop(object);

                    {
                        // This test is a bit weird but ok.
                        let obj = unsafe { reference.upgrade_borrowed_as_unchecked::<PyAny>() };

                        assert!(obj.is_none());
                    }

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    assert!(reference.upgrade().is_some());
                    assert!(reference.upgrade().map_or(false, |obj| obj.is(&object)));

                    drop(object);

                    assert!(reference.upgrade().is_none());

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_borrowed() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    assert!(reference.upgrade_borrowed().is_some());
                    assert!(reference
                        .upgrade_borrowed()
                        .map_or(false, |obj| obj.is(&object)));

                    drop(object);

                    assert!(reference.upgrade_borrowed().is_none());

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_get_object() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    assert!(reference.get_object().is(&object));

                    drop(object);

                    assert!(reference.get_object().is_none());

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_get_object_borrowed() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    assert!(reference.get_object_borrowed().is(&object));

                    drop(object);

                    assert!(reference.get_object_borrowed().is_none());

                    Ok(())
                })
            }
        }

        // under 'abi3-py37' and 'abi3-py38' PyClass cannot be weakreferencable.
        #[cfg(all(feature = "macros", not(all(Py_LIMITED_API, not(Py_3_9)))))]
        mod pyo3_pyclass {
            use super::*;
            use crate::{pyclass, Py};

            #[pyclass(weakref, crate = "crate")]
            struct WeakrefablePyClass {}

            #[test]
            fn test_weakref_proxy_behavior() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object: Bound<'_, WeakrefablePyClass> =
                        Bound::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    assert!(!reference.is(&object));
                    assert!(reference.get_object().is(&object));
                    #[cfg(not(Py_LIMITED_API))]
                    assert_eq!(
                        reference.get_type().to_string(),
                        format!("<class {}>", CLASS_NAME)
                    );

                    assert_eq!(
                        reference.getattr("__class__")?.to_string(),
                        "<class 'builtins.WeakrefablePyClass'>"
                    );
                    #[cfg(not(Py_LIMITED_API))]
                    check_repr(&reference, object.as_any(), Some("WeakrefablePyClass"))?;

                    assert!(reference
                        .getattr("__callback__")
                        .err()
                        .map_or(false, |err| err.is_instance_of::<PyAttributeError>(py)));

                    assert!(reference.call0().err().map_or(false, |err| {
                        let result = err.is_instance_of::<PyTypeError>(py);
                        #[cfg(not(Py_LIMITED_API))]
                        let result = result
                            & (err.value_bound(py).to_string()
                                == format!("{} object is not callable", CLASS_NAME));
                        result
                    }));

                    drop(object);

                    assert!(reference.get_object().is_none());
                    assert!(reference
                        .getattr("__class__")
                        .err()
                        .map_or(false, |err| err.is_instance_of::<PyReferenceError>(py)));
                    #[cfg(not(Py_LIMITED_API))]
                    check_repr(&reference, py.None().bind(py), None)?;

                    assert!(reference
                        .getattr("__callback__")
                        .err()
                        .map_or(false, |err| err.is_instance_of::<PyReferenceError>(py)));

                    assert!(reference.call0().err().map_or(false, |err| {
                        let result = err.is_instance_of::<PyTypeError>(py);
                        #[cfg(not(Py_LIMITED_API))]
                        let result = result
                            & (err.value_bound(py).to_string()
                                == format!("{} object is not callable", CLASS_NAME));
                        result
                    }));

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_as() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object = Py::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(object.bind(py))?;

                    {
                        let obj = reference.upgrade_as::<WeakrefablePyClass>();

                        assert!(obj.is_ok());
                        let obj = obj.unwrap();

                        assert!(obj.is_some());
                        assert!(obj.map_or(false, |obj| obj.as_ptr() == object.as_ptr()));
                    }

                    drop(object);

                    {
                        let obj = reference.upgrade_as::<WeakrefablePyClass>();

                        assert!(obj.is_ok());
                        let obj = obj.unwrap();

                        assert!(obj.is_none());
                    }

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_borrowed_as() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object = Py::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(object.bind(py))?;

                    {
                        let obj = reference.upgrade_borrowed_as::<WeakrefablePyClass>();

                        assert!(obj.is_ok());
                        let obj = obj.unwrap();

                        assert!(obj.is_some());
                        assert!(obj.map_or(false, |obj| obj.as_ptr() == object.as_ptr()));
                    }

                    drop(object);

                    {
                        let obj = reference.upgrade_borrowed_as::<WeakrefablePyClass>();

                        assert!(obj.is_ok());
                        let obj = obj.unwrap();

                        assert!(obj.is_none());
                    }

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_as_unchecked() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object = Py::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(object.bind(py))?;

                    {
                        let obj = unsafe { reference.upgrade_as_unchecked::<WeakrefablePyClass>() };

                        assert!(obj.is_some());
                        assert!(obj.map_or(false, |obj| obj.as_ptr() == object.as_ptr()));
                    }

                    drop(object);

                    {
                        let obj = unsafe { reference.upgrade_as_unchecked::<WeakrefablePyClass>() };

                        assert!(obj.is_none());
                    }

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_borrowed_as_unchecked() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object = Py::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(object.bind(py))?;

                    {
                        let obj = unsafe {
                            reference.upgrade_borrowed_as_unchecked::<WeakrefablePyClass>()
                        };

                        assert!(obj.is_some());
                        assert!(obj.map_or(false, |obj| obj.as_ptr() == object.as_ptr()));
                    }

                    drop(object);

                    {
                        let obj = unsafe {
                            reference.upgrade_borrowed_as_unchecked::<WeakrefablePyClass>()
                        };

                        assert!(obj.is_none());
                    }

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object = Py::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(object.bind(py))?;

                    assert!(reference.upgrade().is_some());
                    assert!(reference.upgrade().map_or(false, |obj| obj.is(&object)));

                    drop(object);

                    assert!(reference.upgrade().is_none());

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_borrowed() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object = Py::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(object.bind(py))?;

                    assert!(reference.upgrade_borrowed().is_some());
                    assert!(reference
                        .upgrade_borrowed()
                        .map_or(false, |obj| obj.is(&object)));

                    drop(object);

                    assert!(reference.upgrade_borrowed().is_none());

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_get_object() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object = Py::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(object.bind(py))?;

                    assert!(reference.get_object().is(&object));

                    drop(object);

                    assert!(reference.get_object().is_none());

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_get_object_borrowed() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object = Py::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(object.bind(py))?;

                    assert!(reference.get_object_borrowed().is(&object));

                    drop(object);

                    assert!(reference.get_object_borrowed().is_none());

                    Ok(())
                })
            }
        }
    }

    mod callable_proxy {
        use super::*;

        #[cfg(all(not(Py_LIMITED_API), Py_3_10))]
        const CLASS_NAME: &str = "<class 'weakref.CallableProxyType'>";
        #[cfg(all(not(Py_LIMITED_API), not(Py_3_10)))]
        const CLASS_NAME: &str = "<class 'weakcallableproxy'>";

        mod python_class {
            use super::*;
            use crate::{py_result_ext::PyResultExt, types::PyType};

            fn get_type(py: Python<'_>) -> PyResult<Bound<'_, PyType>> {
                py.run_bound(
                    "class A:\n    def __call__(self):\n        return 'This class is callable!'\n",
                    None,
                    None,
                )?;
                py.eval_bound("A", None, None).downcast_into::<PyType>()
            }

            #[test]
            fn test_weakref_proxy_behavior() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    assert!(!reference.is(&object));
                    assert!(reference.get_object().is(&object));
                    #[cfg(not(Py_LIMITED_API))]
                    assert_eq!(reference.get_type().to_string(), CLASS_NAME);

                    assert_eq!(
                        reference.getattr("__class__")?.to_string(),
                        "<class '__main__.A'>"
                    );
                    #[cfg(not(Py_LIMITED_API))]
                    check_repr(&reference, &object, Some("A"))?;

                    assert!(reference
                        .getattr("__callback__")
                        .err()
                        .map_or(false, |err| err.is_instance_of::<PyAttributeError>(py)));

                    assert_eq!(reference.call0()?.to_string(), "This class is callable!");

                    drop(object);

                    assert!(reference.get_object().is_none());
                    assert!(reference
                        .getattr("__class__")
                        .err()
                        .map_or(false, |err| err.is_instance_of::<PyReferenceError>(py)));
                    #[cfg(not(Py_LIMITED_API))]
                    check_repr(&reference, py.None().bind(py), None)?;

                    assert!(reference
                        .getattr("__callback__")
                        .err()
                        .map_or(false, |err| err.is_instance_of::<PyReferenceError>(py)));

                    assert!(reference
                        .call0()
                        .err()
                        .map_or(false, |err| err.is_instance_of::<PyReferenceError>(py)
                            & (err.value_bound(py).to_string()
                                == "weakly-referenced object no longer exists")));

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_as() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    {
                        // This test is a bit weird but ok.
                        let obj = reference.upgrade_as::<PyAny>();

                        assert!(obj.is_ok());
                        let obj = obj.unwrap();

                        assert!(obj.is_some());
                        assert!(obj.map_or(false, |obj| obj.as_ptr() == object.as_ptr()
                            && obj.is_exact_instance(&class)));
                    }

                    drop(object);

                    {
                        // This test is a bit weird but ok.
                        let obj = reference.upgrade_as::<PyAny>();

                        assert!(obj.is_ok());
                        let obj = obj.unwrap();

                        assert!(obj.is_none());
                    }

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_borrowed_as() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    {
                        // This test is a bit weird but ok.
                        let obj = reference.upgrade_borrowed_as::<PyAny>();

                        assert!(obj.is_ok());
                        let obj = obj.unwrap();

                        assert!(obj.is_some());
                        assert!(obj.map_or(false, |obj| obj.as_ptr() == object.as_ptr()
                            && obj.is_exact_instance(&class)));
                    }

                    drop(object);

                    {
                        // This test is a bit weird but ok.
                        let obj = reference.upgrade_borrowed_as::<PyAny>();

                        assert!(obj.is_ok());
                        let obj = obj.unwrap();

                        assert!(obj.is_none());
                    }

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_as_unchecked() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    {
                        // This test is a bit weird but ok.
                        let obj = unsafe { reference.upgrade_as_unchecked::<PyAny>() };

                        assert!(obj.is_some());
                        assert!(obj.map_or(false, |obj| obj.as_ptr() == object.as_ptr()
                            && obj.is_exact_instance(&class)));
                    }

                    drop(object);

                    {
                        // This test is a bit weird but ok.
                        let obj = unsafe { reference.upgrade_as_unchecked::<PyAny>() };

                        assert!(obj.is_none());
                    }

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_borrowed_as_unchecked() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    {
                        // This test is a bit weird but ok.
                        let obj = unsafe { reference.upgrade_borrowed_as_unchecked::<PyAny>() };

                        assert!(obj.is_some());
                        assert!(obj.map_or(false, |obj| obj.as_ptr() == object.as_ptr()
                            && obj.is_exact_instance(&class)));
                    }

                    drop(object);

                    {
                        // This test is a bit weird but ok.
                        let obj = unsafe { reference.upgrade_borrowed_as_unchecked::<PyAny>() };

                        assert!(obj.is_none());
                    }

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    assert!(reference.upgrade().is_some());
                    assert!(reference.upgrade().map_or(false, |obj| obj.is(&object)));

                    drop(object);

                    assert!(reference.upgrade().is_none());

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_borrowed() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    assert!(reference.upgrade_borrowed().is_some());
                    assert!(reference
                        .upgrade_borrowed()
                        .map_or(false, |obj| obj.is(&object)));

                    drop(object);

                    assert!(reference.upgrade_borrowed().is_none());

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_get_object() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    assert!(reference.get_object().is(&object));

                    drop(object);

                    assert!(reference.get_object().is_none());

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_get_object_borrowed() -> PyResult<()> {
                Python::with_gil(|py| {
                    let class = get_type(py)?;
                    let object = class.call0()?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    assert!(reference.get_object_borrowed().is(&object));

                    drop(object);

                    assert!(reference.get_object_borrowed().is_none());

                    Ok(())
                })
            }
        }

        // under 'abi3-py37' and 'abi3-py38' PyClass cannot be weakreferencable.
        #[cfg(all(feature = "macros", not(all(Py_LIMITED_API, not(Py_3_9)))))]
        mod pyo3_pyclass {
            use super::*;
            use crate::{pyclass, pymethods, Py};

            #[pyclass(weakref, crate = "crate")]
            struct WeakrefablePyClass {}

            #[pymethods(crate = "crate")]
            impl WeakrefablePyClass {
                fn __call__(&self) -> &str {
                    "This class is callable!"
                }
            }

            #[test]
            fn test_weakref_proxy_behavior() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object: Bound<'_, WeakrefablePyClass> =
                        Bound::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(&object)?;

                    assert!(!reference.is(&object));
                    assert!(reference.get_object().is(&object));
                    #[cfg(not(Py_LIMITED_API))]
                    assert_eq!(reference.get_type().to_string(), CLASS_NAME);

                    assert_eq!(
                        reference.getattr("__class__")?.to_string(),
                        "<class 'builtins.WeakrefablePyClass'>"
                    );
                    #[cfg(not(Py_LIMITED_API))]
                    check_repr(&reference, object.as_any(), Some("WeakrefablePyClass"))?;

                    assert!(reference
                        .getattr("__callback__")
                        .err()
                        .map_or(false, |err| err.is_instance_of::<PyAttributeError>(py)));

                    assert_eq!(reference.call0()?.to_string(), "This class is callable!");

                    drop(object);

                    assert!(reference.get_object().is_none());
                    assert!(reference
                        .getattr("__class__")
                        .err()
                        .map_or(false, |err| err.is_instance_of::<PyReferenceError>(py)));
                    #[cfg(not(Py_LIMITED_API))]
                    check_repr(&reference, py.None().bind(py), None)?;

                    assert!(reference
                        .getattr("__callback__")
                        .err()
                        .map_or(false, |err| err.is_instance_of::<PyReferenceError>(py)));

                    assert!(reference
                        .call0()
                        .err()
                        .map_or(false, |err| err.is_instance_of::<PyReferenceError>(py)
                            & (err.value_bound(py).to_string()
                                == "weakly-referenced object no longer exists")));

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_as() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object = Py::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(object.bind(py))?;

                    {
                        let obj = reference.upgrade_as::<WeakrefablePyClass>();

                        assert!(obj.is_ok());
                        let obj = obj.unwrap();

                        assert!(obj.is_some());
                        assert!(obj.map_or(false, |obj| obj.as_ptr() == object.as_ptr()));
                    }

                    drop(object);

                    {
                        let obj = reference.upgrade_as::<WeakrefablePyClass>();

                        assert!(obj.is_ok());
                        let obj = obj.unwrap();

                        assert!(obj.is_none());
                    }

                    Ok(())
                })
            }
            #[test]
            fn test_weakref_upgrade_borrowed_as() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object = Py::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(object.bind(py))?;

                    {
                        let obj = reference.upgrade_borrowed_as::<WeakrefablePyClass>();

                        assert!(obj.is_ok());
                        let obj = obj.unwrap();

                        assert!(obj.is_some());
                        assert!(obj.map_or(false, |obj| obj.as_ptr() == object.as_ptr()));
                    }

                    drop(object);

                    {
                        let obj = reference.upgrade_borrowed_as::<WeakrefablePyClass>();

                        assert!(obj.is_ok());
                        let obj = obj.unwrap();

                        assert!(obj.is_none());
                    }

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_as_unchecked() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object = Py::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(object.bind(py))?;

                    {
                        let obj = unsafe { reference.upgrade_as_unchecked::<WeakrefablePyClass>() };

                        assert!(obj.is_some());
                        assert!(obj.map_or(false, |obj| obj.as_ptr() == object.as_ptr()));
                    }

                    drop(object);

                    {
                        let obj = unsafe { reference.upgrade_as_unchecked::<WeakrefablePyClass>() };

                        assert!(obj.is_none());
                    }

                    Ok(())
                })
            }
            #[test]
            fn test_weakref_upgrade_borrowed_as_unchecked() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object = Py::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(object.bind(py))?;

                    {
                        let obj = unsafe {
                            reference.upgrade_borrowed_as_unchecked::<WeakrefablePyClass>()
                        };

                        assert!(obj.is_some());
                        assert!(obj.map_or(false, |obj| obj.as_ptr() == object.as_ptr()));
                    }

                    drop(object);

                    {
                        let obj = unsafe {
                            reference.upgrade_borrowed_as_unchecked::<WeakrefablePyClass>()
                        };

                        assert!(obj.is_none());
                    }

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object = Py::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(object.bind(py))?;

                    assert!(reference.upgrade().is_some());
                    assert!(reference.upgrade().map_or(false, |obj| obj.is(&object)));

                    drop(object);

                    assert!(reference.upgrade().is_none());

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_upgrade_borrowed() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object = Py::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(object.bind(py))?;

                    assert!(reference.upgrade_borrowed().is_some());
                    assert!(reference
                        .upgrade_borrowed()
                        .map_or(false, |obj| obj.is(&object)));

                    drop(object);

                    assert!(reference.upgrade_borrowed().is_none());

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_get_object() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object = Py::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(object.bind(py))?;

                    assert!(reference.get_object().is(&object));

                    drop(object);

                    assert!(reference.get_object().is_none());

                    Ok(())
                })
            }

            #[test]
            fn test_weakref_get_object_borrowed() -> PyResult<()> {
                Python::with_gil(|py| {
                    let object = Py::new(py, WeakrefablePyClass {})?;
                    let reference = PyWeakrefProxy::new_bound(object.bind(py))?;

                    assert!(reference.get_object_borrowed().is(&object));

                    drop(object);

                    assert!(reference.get_object_borrowed().is_none());

                    Ok(())
                })
            }
        }
    }
}
