Generated tests: only assert scroll width/height for nodes that are s…

…croll containers (#726)

* Fix documentation of scroll_height method

* Only assert scroll width/height for scrollable nodes

* Add "end" padding to computed content size

scripts/gentest/src/main.rs

@@ -238,6 +238,14 @@ fn generate_test(name: impl AsRef<str>, description: &Value) -> TokenStream {
 fn generate_assertions(ident: &str, node: &Value, use_rounding: bool) -> TokenStream {
     let layout = if use_rounding { &node["smartRoundedLayout"] } else { &node["unroundedLayout"] };
 
+    fn is_scrollable(overflow: &Value) -> bool {
+        match overflow {
+            Value::String(ref value) => matches!(value.as_ref(), "hidden" | "scroll" | "auto"),
+            _ => false,
+        }
+    }
+    let is_scroll_container = is_scrollable(&node["style"]["overflowX"]) || is_scrollable(&node["style"]["overflowY"]);
+
     let read_f32 = |s: &str| layout[s].as_f64().unwrap() as f32;
     let read_naive_f32 = |s: &str| node["naivelyRoundedLayout"][s].as_f64().unwrap() as f32;
     let width = read_f32("width");
@@ -260,33 +268,40 @@ fn generate_assertions(ident: &str, node: &Value, use_rounding: bool) -> TokenSt
 
     let ident = Ident::new(ident, Span::call_site());
 
+    // The scrollWidth reading from chrome is only accurate if the node is scroll container. So only assert in that case.
+    // TODO: accurately test content size in the non-scroll-container case.
+    let scroll_assertions = if is_scroll_container {
+        quote!(
+            #[cfg(feature = "content_size")]
+            assert_eq!(layout.scroll_width(), #scroll_width, "scroll_width of node {:?}. Expected {}. Actual {}", #ident, #scroll_width, layout.scroll_width());
+            #[cfg(feature = "content_size")]
+            assert_eq!(layout.scroll_height(), #scroll_height, "scroll_height of node {:?}. Expected {}. Actual {}", #ident, #scroll_height, layout.scroll_height());
+        )
+    } else {
+        quote!()
+    };
+
     if use_rounding {
         quote!(
-            #[cfg_attr(not(feature = "content_size"), allow(unused_variables))]
-            let layout @ Layout { size, location, .. } = taffy.layout(#ident).unwrap();
+            let layout = taffy.layout(#ident).unwrap();
+            let Layout { size, location, .. } = layout;
             assert_eq!(size.width, #width, "width of node {:?}. Expected {}. Actual {}", #ident,  #width, size.width);
             assert_eq!(size.height, #height, "height of node {:?}. Expected {}. Actual {}", #ident,  #height, size.height);
             assert_eq!(location.x, #x, "x of node {:?}. Expected {}. Actual {}", #ident,  #x, location.x);
             assert_eq!(location.y, #y, "y of node {:?}. Expected {}. Actual {}", #ident,  #y, location.y);
-            #[cfg(feature = "content_size")]
-            assert_eq!(layout.scroll_width(), #scroll_width, "scroll_width of node {:?}. Expected {}. Actual {}", #ident, #scroll_width, layout.scroll_width());
-            #[cfg(feature = "content_size")]
-            assert_eq!(layout.scroll_height(), #scroll_height, "scroll_height of node {:?}. Expected {}. Actual {}", #ident, #scroll_height, layout.scroll_height());
+            #scroll_assertions
 
             #children
         )
     } else {
         quote!(
-            #[cfg_attr(not(feature = "content_size"), allow(unused_variables))]
-            let layout @ Layout { size, location, .. } = taffy.layout(#ident).unwrap();
+            let layout = taffy.layout(#ident).unwrap();
+            let Layout { size, location, .. } = layout;
             assert!((size.width - #width).abs() < 0.1, "width of node {:?}. Expected {}. Actual {}", #ident, #width, size.width);
             assert!((size.height - #height).abs() < 0.1, "height of node {:?}. Expected {}. Actual {}", #ident, #height, size.height);
             assert!((location.x - #x).abs() < 0.1, "x of node {:?}. Expected {}. Actual {}", #ident, #x, location.x);
             assert!((location.y - #y).abs() < 0.1, "y of node {:?}. Expected {}. Actual {}", #ident, #y, location.y);
-            #[cfg(feature = "content_size")]
-            assert!((layout.scroll_width() - #scroll_width).abs() < 0.1, "scroll_width of node {:?}. Expected {}. Actual {}", #ident, #scroll_width, layout.scroll_width());
-            #[cfg(feature = "content_size")]
-            assert!((layout.scroll_height() - #scroll_height).abs() < 0.1, "scroll_height of node {:?}. Expected {}. Actual {}", #ident, #scroll_height, layout.scroll_height());
+            #scroll_assertions
 
             #children
         )

src/compute/flexbox.rs

@@ -1999,6 +1999,9 @@ fn final_layout_pass(
         }
     }
 
+    content_size.width += constants.content_box_inset.right - constants.border.right - constants.scrollbar_gutter.x;
+    content_size.height += constants.content_box_inset.bottom - constants.border.bottom - constants.scrollbar_gutter.y;
+
     content_size
 }
 

src/tree/layout.rs

@@ -306,8 +306,8 @@ impl Layout {
         )
     }
 
-    /// Return the scroll width of the node.
-    /// The scroll width is the difference between the width and the content width, floored at zero
+    /// Return the scroll height of the node.
+    /// The scroll height is the difference between the height and the content height, floored at zero
     pub fn scroll_height(&self) -> f32 {
         f32_max(
             0.0,