From da0b0eeae7946b148e98220647b8cdca11970488 Mon Sep 17 00:00:00 2001
From: ldm0 <ldm2993593805@163.com>
Date: Mon, 19 Oct 2026 20:40:34 +0800
Subject: [PATCH] test(css): cover Color 5 zero weights and percentage
 serialization

Original-commit: 6e9e9a7327d40a0e4d87f6388b88178d50bb4102
---
 moli-css-parse/src/color.rs | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/moli-css-parse/src/color.rs b/moli-css-parse/src/color.rs
index 2fa730973c..3f1577d9c8 100644
--- a/moli-css-parse/src/color.rs
+++ b/moli-css-parse/src/color.rs
@@ -149,6 +149,29 @@ fn absolute_srgb_bytes(color: AbsoluteColor) -> [u8; 4] {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use style_traits::ToCss;
+
+    #[test]
+    fn color_mix_preserves_zero_weights_and_serializes_omitted_percentages() {
+        // CSS Color 5 no longer rejects a zero-sum mix. The frozen WPT
+        // snapshot predates this rule and the percentage serialization update.
+        for value in [
+            "color-mix(in srgb, red 0%, blue 0%)",
+            "color-mix(in srgb, red 0%)",
+            "color-mix(in srgb, red 0%, green 0%, blue 0%)",
+        ] {
+            assert!(parse_specified_color(value).is_some(), "{value}");
+            assert_eq!(parse_css_color_to_srgb_bytes(value).unwrap()[3], 0);
+        }
+        assert!(parse_specified_color("color-mix(in srgb, red -1%, blue)").is_none());
+        assert!(parse_specified_color("color-mix(in srgb, red 101%, blue)").is_none());
+        assert_eq!(
+            parse_specified_color("color-mix(contrast-color(blue) 100%, purple)")
+                .unwrap()
+                .to_css_string(),
+            "color-mix(contrast-color(blue) 100%, purple 0%)",
+        );
+    }
 
     #[test]
     fn css_colors_convert_to_opaque_srgb_hex() {