Trailing whitespace is not handled correctly

[wfdewith]

In my attempts to implement min_content_width and max_content_width, I ran into another issue.

I've written the following test:

#[test]
fn trailing_whitespace() {
    let mut env = testenv!();

    let text = "AAA   BBB";
    let mut builder = env.builder(text);
    let mut layout = builder.build(text);
    layout.break_all_lines(Some(45.));
    layout.align(None, Alignment::Start, false);
    println!("width = {}", layout.width());
    println!("full_width = {}", layout.full_width());
    for (i, line) in layout.lines().enumerate() {
        println!("line {}, trailing_whitespace = {}", i, line.metrics().trailing_whitespace);
    }
    env.check_layout_snapshot(&layout);
}

This prints and renders the following:

width = 43.195313
full_width = 43.195313
line 0, trailing_whitespace = 0
line 1, trailing_whitespace = 0

(I added the grey block to make the actual layout width and height visible with the patch below.)

Patch

diff --git a/parley/src/tests/utils/renderer.rs b/parley/src/tests/utils/renderer.rs
index 2169eb7..a5d6736 100644
--- a/parley/src/tests/utils/renderer.rs
+++ b/parley/src/tests/utils/renderer.rs
@@ -61,6 +61,15 @@ pub(crate) fn render_layout(
 
     let mut pen = TinySkiaPen::new(img.as_mut());
 
+    draw_rect(
+        &mut pen,
+        fpadding,
+        fpadding,
+        width as f32,
+        height as f32,
+        Color::from_rgba8(220, 220, 220, 255),
+    );
+
     for rect in selection_rects {
         draw_rect(
             &mut pen,

I would expect that the full_width of this layout includes the whitespace, while the width does not. Additionally, I would expect the first line to have trailing_whitespace > 0 in its metrics.