Add 'HorizontalScroll'.

Related issues: #1957.

CHANGELOG.md

@@ -28,6 +28,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Breaking change: Added `toggle_button` attribute to RadioButton and Checkbox events, replaces `input` https://github.com/Textualize/textual/pull/1940
 - A percentage alpha can now be applied to a border https://github.com/Textualize/textual/issues/1863
 - Added `Color.multiply_alpha`.
+- Added `HorizontalScroll` https://github.com/Textualize/textual/issues/1957
 
 ### Fixed
 

src/textual/containers.py

@@ -37,6 +37,18 @@ class Horizontal(Widget):
     """
 
 
+class HorizontalScroll(Widget):
+    """A container widget which aligns children horizontally and overflows if needed."""
+
+    DEFAULT_CSS = """
+    HorizontalScroll {
+        height: 1fr;
+        layout: horizontal;
+        overflow-x: auto;
+    }
+    """
+
+
 class Grid(Widget):
     """A container widget with grid alignment."""
 

tests/test_containers.py

@@ -0,0 +1,34 @@
+"""Test basic functioning of some containers."""
+
+from textual.app import App, ComposeResult
+from textual.containers import Horizontal, HorizontalScroll
+from textual.widgets import Label
+
+
+async def test_horizontal_vs_horizontalscroll_scrolling():
+    """Check the default scrollbar behaviours for Horizontal and HorizontalScroll."""
+
+    class HorizontalsApp(App[None]):
+        CSS = """
+        Screen {
+            layout: vertical;
+        }
+        """
+
+        def compose(self) -> ComposeResult:
+            with Horizontal():
+                for _ in range(10):
+                    yield Label("How is life going? " * 3 + " | ")
+            with HorizontalScroll():
+                for _ in range(10):
+                    yield Label("How is life going? " * 3 + " | ")
+
+    WIDTH = 80
+    HEIGHT = 24
+    app = HorizontalsApp()
+    async with app.run_test(size=(WIDTH, HEIGHT)):
+        horizontal = app.query_one(Horizontal)
+        horizontal_scroll = app.query_one(HorizontalScroll)
+        assert horizontal.size.height == horizontal_scroll.size.height
+        assert horizontal.scrollbars_enabled == (False, False)
+        assert horizontal_scroll.scrollbars_enabled == (False, True)