Add changelog entry and test

CHANGELOG.md

@@ -5,6 +5,10 @@ PyO3 versions, please see the [migration guide](https://pyo3.rs/master/migration
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+### Changed
+- Change `PyIterator` to be consistent with other native types: it is now used as `&PyIterator` instead of `PyIterator<'a>`. [#1176](https://github.com/PyO3/pyo3/pull/1176)
+
 ## [0.12.2] - 2020-10-12
 ### Added
 - Add support for keyword-only arguments without default values in `#[pyfunction]`. [#1209](https://github.com/PyO3/pyo3/pull/1209)

src/types/iterator.rs

@@ -96,8 +96,7 @@ mod tests {
     use crate::exceptions::PyTypeError;
     use crate::gil::GILPool;
     use crate::types::{PyDict, PyList};
-    use crate::Python;
-    use crate::ToPyObject;
+    use crate::{Python, Py, PyAny, ToPyObject, PyTryFrom};
     use indoc::indoc;
 
     #[test]
@@ -199,4 +198,13 @@ mod tests {
 
         assert!(err.is_instance::<PyTypeError>(py))
     }
+
+    #[test]
+    fn iterator_try_from() {
+        let gil_guard = Python::acquire_gil();
+        let py = gil_guard.python();
+        let obj: Py<PyAny> = vec![10, 20].to_object(py).as_ref(py).iter().unwrap().into();
+        let iter: &PyIterator = PyIterator::try_from(obj.as_ref(py)).unwrap();
+        assert_eq!(obj, iter.into());
+    }
 }