Macro holochain::meta_mock

macro_rules! meta_mock {
    () => { ... };
    ($fun:ident) => { ... };
    ($fun:ident, $data:expr) => { ... };
    ($fun:ident, $data:expr, $match_fn:expr) => { ... };
}

Create metadata mocks easily by passing in expected functions, return data and with_f checks