Serialize writes in the test HTTP API

Parallel e2e tests hit the repo's sigrefs lock when creating COBs
concurrently, which the Tauri avoids by running these commands on
the main thread serially.

crates/test-http-api/Cargo.toml

@@ -19,5 +19,5 @@ radicle-types = { path = "../radicle-types" }
 serde = { version = "1.0.0", features = ["derive"] }
 serde_json = { version = "1.0.0", features = ["preserve_order"] }
 thiserror = { version = "2.0.12" }
-tokio = { version = "1.45", default-features = false, features = ["macros", "rt-multi-thread"] }
+tokio = { version = "1.45", default-features = false, features = ["macros", "rt-multi-thread", "sync"] }
 tower-http = { version = "0.6.8", default-features = false, features = ["cors", "set-header"] }

crates/test-http-api/src/api.rs

@@ -3,12 +3,14 @@ use std::path::PathBuf;
 use std::sync::Arc;
 
 use axum::Router;
-use axum::extract::State;
-use axum::response::{IntoResponse, Json};
+use axum::extract::{Request, State};
+use axum::middleware::{self, Next};
+use axum::response::{IntoResponse, Json, Response};
 use axum::routing::post;
 use hyper::Method;
 use hyper::header::CONTENT_TYPE;
 use serde::{Deserialize, Serialize};
+use tokio::sync::Mutex;
 use tower_http::cors::{self, CorsLayer};
 
 use radicle::node::NodeId;
@@ -73,6 +75,22 @@ impl Context {
 }
 
 pub fn router(ctx: Context) -> Router {
+    let writes = Router::new()
+        .route("/seed", post(seed_handler))
+        .route("/unseed", post(unseed_handler))
+        .route("/clean", post(clean_handler))
+        .route("/create_issue", post(create_issue_handler))
+        .route("/create_issue_comment", post(create_issue_comment_handler))
+        .route("/edit_issue", post(edit_issue_handler))
+        .route("/delete_issue", post(delete_issue_handler))
+        .route("/edit_patch", post(edit_patch_handler))
+        .route("/create_patch_review", post(create_patch_review_handler))
+        .route("/delete_patch", post(delete_patch_handler))
+        .route_layer(middleware::from_fn_with_state(
+            Arc::new(Mutex::new(())),
+            serialize_writes,
+        ));
+
     Router::new()
         .route("/config", post(config_handler))
         .route("/authenticate", post(auth_handler))
@@ -83,9 +101,6 @@ pub fn router(ctx: Context) -> Router {
             "/seeded_not_replicated",
             post(seeded_not_replicated_handler),
         )
-        .route("/seed", post(seed_handler))
-        .route("/unseed", post(unseed_handler))
-        .route("/clean", post(clean_handler))
         .route("/repo_by_id", post(repo_handler))
         .route("/list_repo_refs", post(list_repo_refs_handler))
         .route("/identity_by_repo", post(identity_handler))
@@ -111,18 +126,11 @@ pub fn router(ctx: Context) -> Router {
         .route("/repo_commit_count", post(repo_commit_count_handler))
         .route("/repo_commit", post(repo_commit_handler))
         .route("/list_issues", post(issues_handler))
-        .route("/create_issue", post(create_issue_handler))
-        .route("/create_issue_comment", post(create_issue_comment_handler))
-        .route("/edit_issue", post(edit_issue_handler))
         .route("/issue_by_id", post(issue_handler))
         .route("/comment_threads_by_issue_id", post(issue_threads_handler))
-        .route("/delete_issue", post(delete_issue_handler))
         .route("/list_patches", post(patches_handler))
         .route("/patch_by_id", post(patch_handler))
         .route("/revisions_by_patch", post(revision_handler))
-        .route("/edit_patch", post(edit_patch_handler))
-        .route("/create_patch_review", post(create_patch_review_handler))
-        .route("/delete_patch", post(delete_patch_handler))
         .route("/get_embed", post(get_embeds_handler))
         .route("/save_embed_by_path", post(save_embed_handler))
         .route("/save_embed_by_clipboard", post(save_embed_handler))
@@ -132,6 +140,7 @@ pub fn router(ctx: Context) -> Router {
         .route("/list_notifications", post(list_notifications_handler))
         .route("/notification_count", post(notification_count_handler))
         .route("/clear_notifications", post(clear_notifications_handler))
+        .merge(writes)
         .layer(
             CorsLayer::new()
                 .allow_origin(cors::Any)
@@ -141,6 +150,15 @@ pub fn router(ctx: Context) -> Router {
         .with_state(ctx)
 }
 
+async fn serialize_writes(
+    State(lock): State<Arc<Mutex<()>>>,
+    request: Request,
+    next: Next,
+) -> Response {
+    let _guard = lock.lock().await;
+    next.run(request).await
+}
+
 async fn config_handler(State(ctx): State<Context>) -> impl IntoResponse {
     let config = ctx.config();