From 76272bcefe2630e88fc5522287f4980598aba3d7 Mon Sep 17 00:00:00 2001
From: Dave Pearson <davep@davep.org>
Date: Wed, 18 Jan 2023 10:42:42 +0000
Subject: [PATCH] Extend ListView test to test an empty inherited list

For testing permutations of #1588.
---
 tests/listview/test_inherit_listview.py | 29 ++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/tests/listview/test_inherit_listview.py b/tests/listview/test_inherit_listview.py
index bb9197646d..2f147a28a5 100644
--- a/tests/listview/test_inherit_listview.py
+++ b/tests/listview/test_inherit_listview.py
@@ -3,23 +3,42 @@
 
 
 class MyListView(ListView):
+    """Test child class of a ListView."""
+
+    def __init__(self, items: int = 0) -> None:
+        super().__init__()
+        self._items = items
+
     def compose(self) -> ComposeResult:
         """Compose the child widgets."""
-        for n in range(20):
-            yield ListView(Label(f"This is item {n}"))
+        for n in range(self._items):
+            yield ListItem(Label(f"This is item {n}"))
 
 
 class ListViewApp(App[None]):
     """ListView test app."""
 
+    def __init__(self, items: int = 0) -> None:
+        super().__init__()
+        self._items = items
+
     def compose(self) -> ComposeResult:
         """Compose the child widgets."""
-        yield MyListView()
+        yield MyListView(self._items)
 
 
-async def test_inherited_list_view() -> None:
-    """A self-populating inherited ListView should work as normal."""
+async def test_empty_inherited_list_view() -> None:
+    """An empty self-populating inherited ListView should work as expected."""
     async with ListViewApp().run_test() as pilot:
+        await pilot.press("tab")
+        assert pilot.app.query_one(MyListView).index is None
+        await pilot.press("down")
+        assert pilot.app.query_one(MyListView).index is None
+
+
+async def test_populated_inherited_list_view() -> None:
+    """A self-populating inherited ListView should work as normal."""
+    async with ListViewApp(30).run_test() as pilot:
         await pilot.press("tab")
         assert pilot.app.query_one(MyListView).index == 0
         await pilot.press("down")