def METHOD_NAME(self):
    for inp, exp in [('nothing to escape', 'nothing to escape'),
                     ('still nothing $ @', 'still nothing $ @' ),
                     ('1 backslash to 2: \\', '1 backslash to 2: \\\\'),
                     ('3 bs to 6: \\\\\\', '3 bs to 6: \\\\\\\\\\\\'),
                     ('\\' * 1000, '\\' * 2000 ),
                     ('${notvar}', '\\${notvar}'),
                     ('@{notvar}', '\\@{notvar}'),
                     ('${nv} ${nv} @{nv}', '\\${nv} \\${nv} \\@{nv}'),
                     ('\\${already esc}', '\\\\\\${already esc}'),
                     ('\\${ae} \\\\@{ae} \\\\\\@{ae}',
                      '\\\\\\${ae} \\\\\\\\\\@{ae} \\\\\\\\\\\\\\@{ae}'),
                     ('%{reserved}', '\\%{reserved}'),
                     ('&{reserved}', '\\&{reserved}'),
                     ('*{reserved}', '\\*{reserved}'),
                     ('x{notreserved}', 'x{notreserved}'),
                     ('named=arg', 'named\\=arg')]:
        assert_equal(escape(inp), exp, inp)