Bug 1514029. Fix serialization of explicitly case-sensitive attr selectors with a namespace. r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D14493

--HG--
extra : moz-landing-system : lando

servo/components/selectors/parser.rs

@@ -1302,7 +1302,7 @@ impl<Impl: SelectorImpl> ToCss for AttrSelectorWithOptionalNamespace<Impl> {
                     ParsedCaseSensitivity::CaseSensitive |
                     ParsedCaseSensitivity::AsciiCaseInsensitiveIfInHtmlElementInHtmlDocument => {},
                     ParsedCaseSensitivity::AsciiCaseInsensitive => dest.write_str(" i")?,
-                    ParsedCaseSensitivity::ExplicitCaseSensitive => dest.write_str(" i")?,
+                    ParsedCaseSensitivity::ExplicitCaseSensitive => dest.write_str(" s")?,
                 }
             },
         }

testing/web-platform/tests/css/selectors/attribute-selectors/attribute-case/cssom.html

@@ -24,9 +24,11 @@ var tests = [
   ['[foo="bar" i]', '[foo="bar" i]'],
   ['[foo="bar" /**/ i]', '[foo="bar" i]'],
   ['[foo="bar"/**/i]', '[foo="bar" i]'],
+  ['[*|foo="bar" i]', '[*|foo="bar" i]'],
   ['[foo="bar" s]', '[foo="bar" s]'],
   ['[foo="bar" /**/ s]', '[foo="bar" s]'],
   ['[foo="bar"/**/s]', '[foo="bar" s]'],
+  ['[*|foo="bar" s]', '[*|foo="bar" s]'],
 ]
 
 tests.forEach(function(arr) {