texmath-0.12.5: test/writer/mml/stretchVertNest2.test

<<< native
[ EDelimited
    "("
    ")"
    [ Right
        (EDelimited
           "("
           ")"
           [ Right (EFraction NormalFrac (EIdentifier "x") (EIdentifier "y"))
           ])
    ]
]
>>> mml
<?xml version='1.0' ?>
<math display="block" xmlns="http://www.w3.org/1998/Math/MathML">
  <mrow>
    <mo stretchy="true" form="prefix">(</mo>
    <mrow>
      <mo stretchy="true" form="prefix">(</mo>
      <mfrac>
        <mi>x</mi>
        <mi>y</mi>
      </mfrac>
      <mo stretchy="true" form="postfix">)</mo>
    </mrow>
    <mo stretchy="true" form="postfix">)</mo>
  </mrow>
</math>