implement support for the width media query

failing test for correct to_css of "width"

separate test for mq and to_css

implement css serialization for Eq

remove PASS test expectation

remove FIXME

simplify serialization

tests/unit/style/media_queries.rs

@@ -13,6 +13,7 @@ use style::media_queries::*;
 use style::parser::ParserContextExtraData;
 use style::stylesheets::{Stylesheet, Origin, CssRule};
 use style::values::specified;
+use style_traits::ToCss;
 
 pub struct CSSErrorReporterTest;
 
@@ -242,6 +243,18 @@ fn test_mq_expressions() {
         }
     });
 
+    test_media_rule("@media print and (width: 43px) { }", |list, css| {
+        assert!(list.media_queries.len() == 1, css.to_owned());
+        let q = &list.media_queries[0];
+        assert!(q.qualifier == None, css.to_owned());
+        assert!(q.media_type == MediaQueryType::MediaType(MediaType::Print), css.to_owned());
+        assert!(q.expressions.len() == 1, css.to_owned());
+        match q.expressions[0] {
+            Expression::Width(Range::Eq(w)) => assert!(w == specified::Length::Absolute(Au::from_px(43))),
+            _ => panic!("wrong expression type"),
+        }
+    });
+
     test_media_rule("@media fridge and (max-width: 52px) { }", |list, css| {
         assert!(list.media_queries.len() == 1, css.to_owned());
         let q = &list.media_queries[0];
@@ -255,6 +268,16 @@ fn test_mq_expressions() {
     });
 }
 
+#[test]
+fn test_to_css() {
+  test_media_rule("@media print and (width: 43px) { }", |list, _| {
+      let q = &list.media_queries[0];
+      let mut dest = String::new();
+      assert_eq!(Ok(()), q.to_css(&mut dest));
+      assert_eq!(dest, "print and (width: 43px)");
+  });
+}
+
 #[test]
 fn test_mq_multiple_expressions() {
     test_media_rule("@media (min-width: 100px) and (max-width: 200px) { }", |list, css| {

tests/wpt/mozilla/meta/css/matchMedia.html.ini

@@ -6,9 +6,5 @@
   [MediaQueryList.matches for "(min-aspect-ratio: 1/1)"]
     expected: FAIL
 
-  [MediaQueryList.matches for "(width: 200px)"]
-    expected: FAIL
-
   [Resize iframe from 200x100 to 200x50, then to 100x50]
     expected: FAIL
-