css/cssom/shorthand-values.html

<!doctype html>
<head>
  <title>CSS OM: CSS Values</title>
  <link rel="author" title="Divya Manian" href="mailto:manian@adobe.com">
  <link rel="help" href="https://drafts.csswg.org/cssom/#serialize-a-css-declaration-block">
  <meta name="flags" content="dom">
  <meta name="assert" content="Testing Serialization of Shorthand Values">
  <script src="/resources/testharness.js"></script>
  <script src="/resources/testharnessreport.js"></script>
</head>
<body>
    <div id="test"></div>
    <script>
      function test_shorthand_serialization(value, expected) {
        test(function() {
          const div = document.getElementById("test");
          div.style.cssText = value;
          assert_equals(div.style.cssText, expected);
        }, "The serialization of " + value + " should be canonical.");
      }

      var tests = {
        // specified -> expected
        'border: 1px; border-top: 1px;': 'border: 1px;',
        'border: 1px solid red;': 'border: 1px solid red;',
        'border: 1px red;': 'border: 1px red;',
        'border: red;': 'border: red;',
        'border-top: 1px; border-right: 1px; border-bottom: 1px; border-left: 1px;': 'border: 1px;',
        'border-top: 1px; border-right: 2px; border-bottom: 3px; border-left: 4px;': 'border-width: 1px 2px 3px 4px;',
        'border: 1px; border-top: 2px;': 'border-width: 2px 1px 1px;',
        'border: 1px; border-top: 1px !important;': 'border-right-width: 1px; border-bottom-width: 1px; border-left-width: 1px; border-top-width: 1px !important;',
        'border: 1px; border-top-color: red;': 'border-width: 1px; border-top-color: red;',
        'border: solid; border-style: dotted': 'border: dotted;',
        'border-width: 1px;': 'border-width: 1px;',
        'overflow-x: scroll; overflow-y: hidden;': 'overflow: scroll hidden;',
        'overflow-x: scroll; overflow-y: scroll;': 'overflow: scroll;',
        'outline-width: 2px; outline-style: dotted; outline-color: blue;': 'outline: blue dotted 2px;',
        'margin-top: 1px; margin-right: 2px; margin-bottom: 3px; margin-left: 4px;': 'margin: 1px 2px 3px 4px;',
        'list-style-type: circle; list-style-position: inside; list-style-image: initial;': 'list-style: inside circle;',
        'list-style-type: lower-alpha;': 'list-style-type: lower-alpha;',
        'font-family: sans-serif; line-height: 2em; font-size: 3em; font-style: italic; font-weight: bold;': 'font-family: sans-serif; line-height: 2em; font-size: 3em; font-style: italic; font-weight: bold;',
        'padding-top: 1px; padding-right: 2px; padding-bottom: 3px; padding-left: 4px;': 'padding: 1px 2px 3px 4px;'
      }

      for (let test in tests) {
        test_shorthand_serialization(test, tests[test]);
      }
    </script>
 </body>
 </html>