    assert_approx_equals(getBox("msub").width, getBox("msubSub").right - getBox("msubBase").left, e, "msub: width is determined by the left/right sides of base/script (+ some space after script)");
      assert_approx_equals(getBox("msup").width, getBox("msupSup").right - getBox("msupBase").left, e, "msup: width is determined by the left/right sides of base/script (+ some space after script)");
      assert_approx_equals(getBox("msubsup").width, Math.max(getBox("msubsupSub").right, getBox("msubsupSup").righ