You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: tests.rs
    path of file: ./repos/fuel-core/crates/services/sync/src/sync
    
    the code of the file until where you have to start completion: use std::sync::Arc;

use fuel_core_services::stream::IntoBoxStream;
use futures::stream;

use super::*;

#[tokio::test]
async fn test_sync() {
    let height_stream =
        stream::iter([1u32, 2, 3, 4, 5].into_iter().map(BlockHeight::from))
            .map(IncomingHeight::Observed)
        
    
async fn test_sync() {
    let height_stream =
        stream::iter([1u32, 2, 3, 4, 5].into_iter().map(BlockHeight::from))
            .map(IncomingHeight::Observed)
            .into_boxed();
    let state = SharedMutex::new(State::new(None, None));
    let notify = Arc::new(Notify::new());

    let mut s = SyncHeights {
        height_stream,
        state,
        notify,
    };

    while s.sync().await.is_some() {}

    assert_eq!(s.state.apply(|s| s.proposed_height().copied()), Some(5u32));
}