tById("mrow-padding-shorthand").
              getBoundingClientRect();
          assert_approx_equals(b.width, 20 + 50 + 20, epsilon, "element width");
          assert_approx_equals(b.height, 20 + 50 + 20, epsilon, "element height");
      }, "Padding properties on mrow (shorthand)");

      test(function() {
          assert_true(MathMLFeatureDetection.has_mspace());
          var s = measureSpaceAround("mrow-padding-logical")
          assert_approx_equals(s.left, 20, epsilon, "left padding");
         