Function dependencies

tests/query_test.rs:24–34

(case: &Case)

}

fn dependencies(case: &Case) -> HashSet<Aid> {
    let mut deps = HashSet::new();

    for binding in case.plan.into_bindings().iter() {
        if let Binding::Attribute(binding) = binding {
            deps.insert(binding.source_attribute.clone());
        }
    }

    deps
}

fn run_cases(mut cases: Vec<Case>) {
    for case in cases.drain(..) {