feature test {
    lookup single_sub_f1 {
        sub a by A;
    } single_sub_f1;

    lookup single_sub_f2 {
    sub a by b;
    # just to force format 2
    sub X by Y;
    } single_sub_f2;

    lookup multiple_sub {
        sub a by c d;
    } multiple_sub;

    lookup lig_sub {
        sub a a by a_a;
    } lig_sub;

    lookup alt_sub {
        sub a from [a.1 a.2];
    } alt_sub;

    lookup rev_single_sub {
        rsub a a' by a.3;
    } rev_single_sub;
} test;