[
    (src: "{{~foo~}}", exp: [(Expr((true, true), (["foo"], (lo:3, hi:6))), (lo: 0, hi:9))]),
    (src: "{{~ foo~}}", exp: [(Expr((true, true), (["foo"], (lo:4, hi:7))), (lo: 0, hi:10))]),
    (src: "{{~ foo}}", exp: [(Expr((true, false), (["foo"], (lo:4, hi:7))), (lo: 0, hi:9))]),
    (src: "{{foo   ~}}", exp: [(Expr((false, true), (["foo"], (lo:2, hi:5))), (lo: 0, hi:11))]),
    (src: "{{~{foo }~}}", exp: [(Safe((true, true), ("foo", (lo:4, hi:7))), (lo: 0, hi:12))]),
    (src: "{{{foo }~}}", exp: [(Safe((false, true), ("foo", (lo:3, hi:6))), (lo: 0, hi:11))]),
    (src: "{{~{f}~}}", exp: [(Safe((true, true), ("f", (lo:4, hi:5))), (lo: 0, hi:9))]),
    (src: "{{{f}~}}", exp: [(Safe((false, true), ("f", (lo:3, hi:4))), (lo: 0, hi:8))]),
    (src: "{{{f}}}", exp: [(Safe((false, false), ("f", (lo:3, hi:4))), (lo: 0, hi:7))]),
]