Function drain_empty

crates/execution/flashblocks/src/cache.rs:134–138

()

    #[test]
    fn drain_empty() {
        let mut cache = FlashblockCache::new(0);
        let drained = cache.drain(42);
        assert!(drained.is_empty());
    }

    #[test]
    fn rejects_beyond_cache_limit() {