Added test for serialize method

tests/unit/style/properties.rs

@@ -7,6 +7,10 @@ use std::env;
 use std::fs::{File, remove_file};
 use std::path::Path;
 use std::process::Command;
+use std::sync::Arc;
+use style::computed_values::display::T::inline_block;
+use style::properties::{PropertyDeclaration, PropertyDeclarationBlock, DeclaredValue};
+use style::values::specified::{Length, LengthOrPercentageOrAuto, LengthOrPercentage};
 
 #[test]
 fn properties_list_json() {
@@ -51,3 +55,38 @@ fn find_python() -> String {
         "python"
     }.to_owned()
 }
+
+#[test]
+fn property_declaration_block_should_serialize_correctly() {
+    let mut normal = Vec::new();
+    let mut important = Vec::new();
+
+    let length = LengthOrPercentageOrAuto::Length(Length::from_px(70f32));
+    let value = DeclaredValue::Value(length);
+    normal.push(PropertyDeclaration::Width(value));
+
+    let min_height = LengthOrPercentage::Length(Length::from_px(20f32));
+    let value = DeclaredValue::Value(min_height);
+    normal.push(PropertyDeclaration::MinHeight(value));
+
+    let value = DeclaredValue::Value(inline_block);
+    normal.push(PropertyDeclaration::Display(value));
+
+    let height = LengthOrPercentageOrAuto::Length(Length::from_px(20f32));
+    let value = DeclaredValue::Value(height);
+    important.push(PropertyDeclaration::Height(value));
+
+    normal.reverse();
+    important.reverse();
+    let block = PropertyDeclarationBlock {
+        normal: Arc::new(normal),
+        important: Arc::new(important)
+    };
+
+    let css_string = block.serialize();
+
+    assert_eq!(
+        css_string,
+        "width: 70px; min-height: 20px; display: inline-block; height: 20px ! important;"
+    );
+}