Add 'Vertical'.

Related issues: #1957.

tests/test_containers.py

@@ -1,7 +1,14 @@
 """Test basic functioning of some containers."""
 
 from textual.app import App, ComposeResult
-from textual.containers import Center, Horizontal, HorizontalScroll, Middle
+from textual.containers import (
+    Center,
+    Horizontal,
+    HorizontalScroll,
+    Middle,
+    Vertical,
+    VerticalScroll,
+)
 from textual.widgets import Label
 
 
@@ -34,6 +41,35 @@ async def test_horizontal_vs_horizontalscroll_scrolling():
         assert horizontal_scroll.scrollbars_enabled == (False, True)
 
 
+async def test_vertical_vs_verticalscroll_scrolling():
+    """Check the default scrollbar behaviours for `Vertical` and `VerticalScroll`."""
+
+    class VerticalsApp(App[None]):
+        CSS = """
+        Screen {
+            layout: horizontal;
+        }
+        """
+
+        def compose(self) -> ComposeResult:
+            with Vertical():
+                for _ in range(10):
+                    yield Label("How is life going?\n" * 3 + "\n\n")
+            with VerticalScroll():
+                for _ in range(10):
+                    yield Label("How is life going?\n" * 3 + "\n\n")
+
+    WIDTH = 80
+    HEIGHT = 24
+    app = VerticalsApp()
+    async with app.run_test(size=(WIDTH, HEIGHT)):
+        vertical = app.query_one(Vertical)
+        vertical_scroll = app.query_one(VerticalScroll)
+        assert vertical.size.width == vertical_scroll.size.width
+        assert vertical.scrollbars_enabled == (False, False)
+        assert vertical_scroll.scrollbars_enabled == (True, False)
+
+
 async def test_center_container():
     """Check the size of the container `Center`."""