edge case and fix

Author: willmcgugan

src/textual/renderables/bar.py

@@ -86,7 +86,7 @@ def __rich_console__(
         if half_end:
             highlight_bar.append(Text(half_bar_right, style=highlight_style, end=""))
 
-        if self.gradient:
+        if self.gradient is not None:
             _apply_gradient(highlight_bar, self.gradient, width)
         output_bar.append(highlight_bar)
 
@@ -112,13 +112,14 @@ def _apply_gradient(text: Text, gradient: Gradient, width: int) -> None:
     Args:
         text: A Text object.
         gradient: A Textual gradient.
-        width: Width to apply gradient to, or None for full width.
+        width: Width of gradient.
     """
     from_color = Style.from_color
     get_rich_color = gradient.get_rich_color
 
     max_width = width - 1
     if not max_width:
+        text.stylize(from_color(gradient.get_color(0).rich_color))
         return
     text_length = len(text)
     for offset in range(text_length):

tests/test_progress_bar.py

@@ -1,8 +1,12 @@
 import pytest
 from pytest import approx
+from rich.console import Console
+from rich.text import Text
 
 from textual.app import App
+from textual.color import Gradient
 from textual.css.query import NoMatches
+from textual.renderables.bar import _apply_gradient
 from textual.widget import Widget
 from textual.widgets import ProgressBar
 
@@ -169,3 +173,11 @@ def compose(self):
         else:
             with pytest.raises(NoMatches):
                 app.pb.query_one("#eta")
+
+
+def test_apply_gradient():
+    text = Text("foo")
+    gradient = Gradient.from_colors("red", "blue")
+    _apply_gradient(text, gradient, 1)
+    console = Console()
+    assert text.get_style_at_offset(console, 0).color.triplet == (255, 0, 0)