Add some unit testing for RadioSet

tests/toggles/test_radioset.py

@@ -0,0 +1,52 @@
+from __future__ import annotations
+
+from textual.app import App, ComposeResult
+from textual.widgets import RadioButton, RadioSet
+
+
+class RadioSetApp(App[None]):
+    def __init__(self):
+        super().__init__()
+        self.events_received = []
+
+    def compose(self) -> ComposeResult:
+        with RadioSet(id="from_buttons"):
+            yield RadioButton()
+            yield RadioButton()
+            yield RadioButton(value=True)
+        yield RadioSet("One", "True", "Three", id="from_strings")
+
+    def on_radio_set_changed(self, event: RadioSet.Changed) -> None:
+        self.events_received.append(
+            (
+                event.input.id,
+                event.index,
+                [button.value for button in event.input.query(RadioButton)],
+            )
+        )
+
+
+async def test_radio_sets_initial_state():
+    """The initial states of the radio sets should be as we specified."""
+    async with RadioSetApp().run_test() as pilot:
+        assert pilot.app.query_one("#from_buttons", RadioSet).pressed_index == 2
+        assert pilot.app.query_one("#from_buttons", RadioSet).pressed_button is not None
+        assert pilot.app.query_one("#from_strings", RadioSet).pressed_index == -1
+        assert pilot.app.query_one("#from_strings", RadioSet).pressed_button is None
+        assert pilot.app.events_received == []
+
+
+async def test_radio_sets_toggle():
+    """Test the starts of the radio sets after they've been toggled."""
+    async with RadioSetApp().run_test() as pilot:
+        pilot.app.query_one("#from_buttons", RadioSet)._buttons[0].toggle()
+        pilot.app.query_one("#from_strings", RadioSet)._buttons[2].toggle()
+        await pilot.pause()
+        assert pilot.app.query_one("#from_buttons", RadioSet).pressed_index == 0
+        assert pilot.app.query_one("#from_buttons", RadioSet).pressed_button is not None
+        assert pilot.app.query_one("#from_strings", RadioSet).pressed_index == 2
+        assert pilot.app.query_one("#from_strings", RadioSet).pressed_button is not None
+        assert pilot.app.events_received == [
+            ("from_buttons", 0, [True, False, False]),
+            ("from_strings", 2, [False, False, True]),
+        ]