texmath-0.12.5: test/writer/mml/msub-07.test

<<< native
[ ESub (EIdentifier "D") (EIdentifier "y")
, ESymbol Rel "="
, ESub
    (EIdentifier "D")
    (EUnder False (EIdentifier "y") (EPhantom (EIdentifier "s")))
]
>>> mml
<?xml version='1.0' ?>
<math display="block" xmlns="http://www.w3.org/1998/Math/MathML">
  <mrow>
    <msub>
      <mi>D</mi>
      <mi>y</mi>
    </msub>
    <mo>=</mo>
    <msub>
      <mi>D</mi>
      <munder>
        <mi>y</mi>
        <mphantom>
          <mi>s</mi>
        </mphantom>
      </munder>
    </msub>
  </mrow>
</math>