base0021").top - getBox("radical0021").top,
                           v1 + v2, epsilon,
                           "msqrt: vertical gap");
      assert_approx_equals(getBox("base0022").top - getBox("radical0022").top,
                           v1 + v2, epsilon,
                           "mroot: vertical gap");
    }, "RadicalDisplayStyleVerticalGap");

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

      var v1 = 3000 * emToPx;
      var v2 = 1000 * emToPx;
      assert_ap