Add place-self shorthand property (it fails unit-test)

components/style/properties/shorthand/position.mako.rs

@@ -186,3 +186,27 @@
     }
 </%helpers:shorthand>
 
+<%helpers:shorthand name="place-self" sub_properties="align-self justify-self"
+                    spec="https://drafts.csswg.org/css-align/#place-self-property"
+                    products="gecko">
+    use values::specified::align::AlignJustifySelf;
+    use parser::Parse;
+
+    pub fn parse_value(context: &ParserContext, input: &mut Parser) -> Result<Longhands, ()> {
+        let align = AlignJustifySelf::parse(context, input)?;
+        let justify = input.try(|input| AlignJustifySelf::parse(context, input)).unwrap_or(align.clone());
+
+        Ok(Longhands {
+            align_self: align,
+            justify_self: justify,
+        })
+    }
+
+    impl<'a> ToCss for LonghandsToSerialize<'a> {
+        fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+            self.align_self.to_css(dest)?;
+            dest.write_str(" ")?;
+            self.justify_self.to_css(dest)
+        }
+    }
+</%helpers:shorthand>

tests/unit/style/properties/serialization.rs

@@ -1263,4 +1263,21 @@ mod shorthand_serialization {
         let serialization = shorthand_properties_to_string(properties);
         assert_eq!(serialization, "place-content: stretch center;");
     }
+
+    #[test]
+    fn place_self_serialize_all_available_properties() {
+        use style::properties::longhands::align_self::SpecifiedValue as AlignSelf;
+        use style::properties::longhands::justify_self::SpecifiedValue as JustifySelf;
+
+        let mut properties = Vec::new();
+
+        let align = AlignSelf::auto;
+        let justify = JustifySelf::baseline;
+
+        properties.push(PropertyDeclaration::AlignSelf(align));
+        properties.push(PropertyDeclaration::JustifySelf(justify));
+
+        let serialization = shorthand_properties_to_string(properties);
+        assert_eq!(serialization, "place-self: auto baseline;");
+    }
 }