[
(
    src: "{{ @json foo }}",
    exp: [(
        AtHelper((false, false), Json, ([("foo")], (lo:9, hi:12))),
        (lo:0, hi:15)
    )]
),
(
    src: "{{ @json_pretty foo }}",
    exp: [(
        AtHelper((false, false), JsonPretty, ([("foo")], (lo:16, hi:19))),
        (lo:0, hi:22)
    )]
),
]