Make Selected.was_stopped a property

We are already using properties for anything that can be trivially
calculated, so this looks like a good candidate too to make the
interface more consistent.

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

src/frequenz/channels/_select.py

@@ -73,7 +73,7 @@
 
 When a single [receiver][frequenz.channels.Receiver] is stopped, it will be reported
 via the [`Selected`][frequenz.channels.Selected] object. You can use the
-[`was_stopped()`][frequenz.channels.Selected.was_stopped] method to check if the
+[`was_stopped`][frequenz.channels.Selected.was_stopped] method to check if the
 selected [receiver][frequenz.channels.Receiver] was stopped:
 
 ```python show_lines="8:"
@@ -86,15 +86,15 @@
 
 async for selected in select(receiver1, receiver2):
     if selected_from(selected, receiver1):
-        if selected.was_stopped():
+        if selected.was_stopped:
             print("receiver1 was stopped")
             continue
         print(f"Received from receiver1, the next number is: {selected.value + 1}")
     # ...
 ```
 
 Tip:
-    The [`was_stopped()`][frequenz.channels.Selected.was_stopped] method is a
+    The [`was_stopped`][frequenz.channels.Selected.was_stopped] method is a
     convenience method that is equivalent to checking if the
     [`exception`][frequenz.channels.Selected.exception] attribute is an instance of
     [`ReceiverStoppedError`][frequenz.channels.ReceiverStoppedError].
@@ -228,16 +228,9 @@ def exception(self) -> Exception | None:
         """
         return self._exception
 
+    @property
     def was_stopped(self) -> bool:
-        """Check if the selected receiver was stopped.
-
-        Check if the selected receiver raised
-        a [`ReceiverStoppedError`][frequenz.channels.ReceiverStoppedError] while
-        consuming a value.
-
-        Returns:
-            Whether the receiver was stopped.
-        """
+        """Whether the selected receiver was stopped while receiving a value."""
         return isinstance(self._exception, ReceiverStoppedError)
 
     def __str__(self) -> str:

tests/test_select.py

@@ -22,7 +22,7 @@ def test_with_value(self) -> None:
         assert selected_from(selected, recv)
         assert selected.value == 42
         assert selected.exception is None
-        assert not selected.was_stopped()
+        assert not selected.was_stopped
 
     def test_with_exception(self) -> None:
         """Test selected from a receiver with an exception."""
@@ -35,7 +35,7 @@ def test_with_exception(self) -> None:
         with pytest.raises(Exception, match="test"):
             _ = selected.value
         assert selected.exception is exception
-        assert not selected.was_stopped()
+        assert not selected.was_stopped
 
     def test_with_stopped(self) -> None:
         """Test selected from a stopped receiver."""
@@ -51,4 +51,4 @@ def test_with_stopped(self) -> None:
         ):
             _ = selected.value
         assert selected.exception is exception
-        assert selected.was_stopped()
+        assert selected.was_stopped

tests/test_select_integration.py

@@ -90,7 +90,7 @@ def assert_received_from(
         assert selected_from(selected, receiver)
         assert selected.value is None
         assert selected.exception is None
-        assert not selected.was_stopped()
+        assert not selected.was_stopped
         if expected_pending_tasks > 0:
             assert len(asyncio.all_tasks(self.loop)) == expected_pending_tasks
         elif expected_pending_tasks < 0:
@@ -121,7 +121,7 @@ def assert_receiver_stopped(
                 it is 0, no check is performed.
         """
         assert selected_from(selected, receiver)
-        assert selected.was_stopped()
+        assert selected.was_stopped
         assert isinstance(selected.exception, ReceiverStoppedError)
         assert selected.exception.receiver is receiver
         if expected_pending_tasks > 0: