texmath-0.12.5: test/writer/tex/munder-06.test

<<< native
[ EIdentifier "- middle -"
, ESymbol Rel "="
, EUnder
    False
    (EUnder
       False (EIdentifier "- middle -") (EPhantom (EIdentifier "fail")))
    (EPhantom (EIdentifier "fail"))
]
>>> tex
{-\ middle\ -} = \underset{\phantom{fail}}{\underset{\phantom{fail}}{-\ middle\ -}}