    test(function() {
               assert_true(MathMLFeatureDetection.has_operator_spacing());
               var element = document.getElementsByTagName(tag)[1];
               assert_approx_equals(spaceBeforeElement(element), 2 * emToPx, epsilon);
           }, `${tag} (embellished operator, from in-flow children)`);

           test(function() {
               assert_true(MathMLFeatureDetection.has_operator_spacing());
               var element = document.getElementsByTagName(tag)[2];
               a