undingClientRect();
  }

  setup({ explicit_done: true });
  window.addEventListener("load", () => { loadAllFonts().then(runTests); });

  function runTests() {

    test(function() {
      assert_true(MathMLFeatureDetection.has_mspace());

      var v = 5000 * emToPx;
      assert_approx_equals(getBox("den0002").top - getBox("ref0002").bottom,
                           v, epsilon, "mfrac: denominator shift");
    }, "BottomDisplayStyleShiftDown");

    test(function() {
      assert_true(MathMLFeatureDete