Making ordered set reversible (#395)

* made ordered set reversible

* style(pre-commit.ci): auto fixes [...]

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: yfukai

src/psygnal/containers/_evented_set.py

@@ -228,6 +228,10 @@ def __repr__(self) -> str:
         inner = ", ".join(str(x) for x in self._data)
         return f"{self.__class__.__name__}(({inner}))"
 
+    def __reversed__(self) -> Iterator[_T]:
+        """Implement reversed(self)."""
+        return reversed(self._data.keys())
+
 
 class SetEvents(SignalGroup):
     """Events available on [EventedSet][psygnal.containers.EventedSet].

tests/containers/test_evented_set.py

@@ -121,6 +121,16 @@ def test_ordering():
     assert tuple(os_tup) == (24, 16, 4, 5, 6, 8)
 
 
+def test_iterator():
+    tup = (24, 16, 8, 4, 5, 6)
+    os_tup = OrderedSet(tup)
+    es_tup = EventedOrderedSet(tup)
+    assert tuple(iter(os_tup)) == tup
+    assert tuple(reversed(os_tup)) == tuple(reversed(tup))
+    assert tuple(iter(es_tup)) == tup
+    assert tuple(reversed(es_tup)) == tuple(reversed(tup))
+
+
 def test_copy(test_set):
     from copy import copy