snapshot fix

Author: willmcgugan

src/textual/canvas.py

@@ -157,7 +157,7 @@ def __init__(self, width: int, height: int) -> None:
         self._width = width
         self._height = height
         blank_line = " " * width
-        self.lines: list[array[str]] = [array("u", blank_line) for _ in range(height)]
+        self.lines: list[array[str]] = [array("w", blank_line) for _ in range(height)]
         self.box: list[defaultdict[int, Quad]] = [
             defaultdict(lambda: (0, 0, 0, 0)) for _ in range(height)
         ]

tests/snapshot_tests/__snapshots__/test_snapshots/test_alignment_with_auto_and_min_height.svg

@@ -3893,3 +3893,33 @@ def on_mount(self) -> None:
             )
 
     snap_compare(ToastApp())
+
+
+# Thanks Tom Gooding
+def test_alignment_with_auto_and_min_height(snap_compare):
+    """Regression test for https://github.com/Textualize/textual/issues/5608
+    You should see a blue label that is centered both horizontally and vertically
+    within a pink container. The container has auto width and height, but also
+    a min-width of 20 and a min-height of 3.
+    """
+
+    class AlignmentApp(App):
+        CSS = """
+        Container {
+            align: center middle;
+            height: auto;
+            min-height: 3;
+            width: auto;
+            min-width: 20;
+            background: pink;
+        }
+        Label {
+            background: blue;
+        }
+        """
+
+        def compose(self) -> ComposeResult:
+            with Container():
+                yield Label("centered")
+
+    snap_compare(AlignmentApp())