diff --git a/crates/matrix-sdk/src/event_cache/caches/thread/mod.rs b/crates/matrix-sdk/src/event_cache/caches/thread/mod.rs
index df63210b7..c946294c4 100644
--- a/crates/matrix-sdk/src/event_cache/caches/thread/mod.rs
+++ b/crates/matrix-sdk/src/event_cache/caches/thread/mod.rs
@@ -22,13 +22,13 @@ use std::{fmt, sync::Arc};
 
 use matrix_sdk_base::event_cache::{Event, store::EventCacheStoreLock};
 use ruma::{EventId, OwnedEventId, OwnedRoomId, OwnedUserId};
-pub(super) use state::LockedThreadEventCacheState;
 use tokio::sync::{
     Notify,
     broadcast::{Receiver, Sender},
 };
 use tracing::{error, trace};
 
+pub(super) use self::state::LockedThreadEventCacheState;
 use self::{pagination::ThreadPagination, updates::ThreadEventCacheUpdateSender};
 use super::{
     super::Result, EventsOrigin, TimelineVectorDiffs, room::RoomEventCacheLinkedChunkUpdate,
@@ -202,3 +202,143 @@ impl ThreadEventCache {
             .and_then(|(_position, event)| event.event_id()))
     }
 }
+
+#[cfg(all(test, not(target_family = "wasm")))] // This uses the cross-process lock, so needs time support.
+mod timed_tests {
+    use std::sync::Arc;
+
+    use assert_matches::assert_matches;
+    use eyeball_im::VectorDiff;
+    use matrix_sdk_base::{
+        RoomState, ThreadingSupport,
+        cross_process_lock::CrossProcessLockConfig,
+        event_cache::store::{EventCacheStore as _, MemoryStore},
+        linked_chunk::{ChunkContent, LinkedChunkId, lazy_loader::from_all_chunks},
+        store::StoreConfig,
+        sync::{JoinedRoomUpdate, Timeline},
+    };
+    use matrix_sdk_test::{async_test, event_factory::EventFactory};
+    use ruma::{event_id, room_id, user_id};
+
+    use super::super::{
+        super::RoomEventCacheGenericUpdate, TimelineVectorDiffs, room::RoomEventCacheUpdate,
+    };
+    use crate::test_utils::client::MockClientBuilder;
+
+    #[async_test]
+    async fn test_write_to_storage() {
+        let room_id = room_id!("!r0");
+        let thread_root = event_id!("$t0_ev0");
+        let thread_event_id_0 = event_id!("$t0_ev1");
+
+        let f = EventFactory::new().room(room_id).sender(user_id!("@mnt_io:matrix.org"));
+
+        let event_cache_store = Arc::new(MemoryStore::new());
+
+        let client = MockClientBuilder::new(None)
+            .on_builder(|builder| {
+                builder
+                    .store_config(
+                        StoreConfig::new(CrossProcessLockConfig::multi_process("hodor"))
+                            .event_cache_store(event_cache_store.clone()),
+                    )
+                    .with_threading_support(ThreadingSupport::Enabled { with_subscriptions: true })
+            })
+            .build()
+            .await;
+
+        let event_cache = client.event_cache();
+        event_cache.subscribe().unwrap();
+
+        client.base_client().get_or_create_room(room_id, RoomState::Joined);
+        let room = client.get_room(room_id).unwrap();
+
+        let mut generic_stream = event_cache.subscribe_to_room_generic_updates();
+        let (room_event_cache, _drop_handles) = room.event_cache().await.unwrap();
+        let (room_events, mut room_stream) = room_event_cache.subscribe().await.unwrap();
+        let (thread_events, mut thread_stream) =
+            room_event_cache.subscribe_to_thread(thread_root.to_owned()).await.unwrap();
+
+        assert!(room_events.is_empty());
+        assert!(thread_events.is_empty());
+
+        // Propagate an update for a message and a prev-batch token.
+        let timeline = Timeline {
+            limited: true,
+            prev_batch: Some("raclette".to_owned()),
+            events: vec![
+                f.text_msg("salut")
+                    .event_id(thread_event_id_0)
+                    .in_thread(thread_root, thread_root)
+                    .into_event(),
+            ],
+        };
+
+        room_event_cache
+            .handle_joined_room_update(JoinedRoomUpdate { timeline, ..Default::default() })
+            .await
+            .unwrap();
+
+        // Checking the update are corrects.
+        assert_matches!(
+            generic_stream.recv().await,
+            Ok(RoomEventCacheGenericUpdate { room_id: expected_room_id }) => {
+                assert_eq!(expected_room_id, room_id);
+            }
+        );
+        assert!(generic_stream.is_empty());
+
+        assert_matches!(
+            room_stream.recv().await,
+            Ok(RoomEventCacheUpdate::UpdateTimelineEvents(TimelineVectorDiffs { diffs, .. })) => {
+                assert_eq!(diffs.len(), 2);
+                assert_matches!(&diffs[0], VectorDiff::Clear);
+                assert_matches!(&diffs[1], VectorDiff::Append { values: events } => {
+                    assert_eq!(events.len(), 1);
+                    assert_eq!(events[0].event_id().as_deref(), Some(thread_event_id_0));
+                });
+            }
+        );
+        assert!(room_stream.is_empty());
+
+        assert_matches!(
+            thread_stream.recv().await,
+            Ok(TimelineVectorDiffs { diffs, .. }) => {
+                assert_eq!(diffs.len(), 1);
+                assert_matches!(&diffs[0], VectorDiff::Append { values: events } => {
+                    assert_eq!(events.len(), 1);
+                    assert_eq!(events[0].event_id().as_deref(), Some(thread_event_id_0));
+                });
+            }
+        );
+        assert!(thread_stream.is_empty());
+
+        // Check the storage.
+        let linked_chunk = from_all_chunks::<3, _, _>(
+            event_cache_store
+                .load_all_chunks(LinkedChunkId::Thread(room_id, thread_root))
+                .await
+                .unwrap(),
+        )
+        .unwrap()
+        .unwrap();
+
+        assert_eq!(linked_chunk.chunks().count(), 2);
+
+        let mut chunks = linked_chunk.chunks();
+
+        // We start with the gap.
+        assert_matches!(chunks.next().unwrap().content(), ChunkContent::Gap(gap) => {
+            assert_eq!(gap.token, "raclette");
+        });
+
+        // Then we have the stored event.
+        assert_matches!(chunks.next().unwrap().content(), ChunkContent::Items(events) => {
+            assert_eq!(events.len(), 1);
+            assert_eq!(events[0].event_id().as_deref(), Some(thread_event_id_0));
+        });
+
+        // That's all, folks!
+        assert!(chunks.next().is_none());
+    }
+}