feat: add distributed expand/search traversal and e2e graph tests

Extract a shared distributed traversal substrate and reuse it across compute, expansion, and search. Add GraphEngine-grounded end-to-end traversal tests including expand/search plus compute PageRank and weighted SSSP with non-transactional edge setup.

Author: shisoft

src/server/mod.rs

@@ -16,6 +16,7 @@ use crate::graph::GraphEngine;
 use crate::job::logger::JobLogger;
 use crate::server::schema::SchemaContainer;
 use crate::traversal::compute::ComputeService;
+use crate::traversal::expand::distributed::ExpandService;
 
 pub mod general;
 pub mod schema;
@@ -292,6 +293,13 @@ impl MorpheusServer {
         Ok(service_ref)
     }
 
+    pub async fn init_expand_service(&self) -> Result<Arc<ExpandService>, String> {
+        let service = ExpandService::new(self.graph.clone(), self.neb_server.consh.clone());
+        let service_ref = service.clone();
+        self.neb_server.rpc.register_service(&service_ref).await;
+        Ok(service_ref)
+    }
+
     /// Initialize the embedding index service with default configuration
     ///
     /// This sets up the embedding indexer and registers it with Neb.

src/tests/compute/mod.rs

@@ -10,8 +10,8 @@ use crate::traversal::compute::{
 };
 use crate::traversal::compute::apps::{PageRankConfig, PageRankProgram};
 use crate::traversal::compute::apps::SsspProgram;
-use crate::traversal::compute::vertex_set::VertexSetManifest;
-use crate::traversal::compute::vertex_set::VertexSetShard;
+use crate::traversal::dist::VertexSetManifest;
+use crate::traversal::dist::VertexSetShard;
 
 struct TestCodec;
 

src/tests/dist/mod.rs

@@ -0,0 +1,11 @@
+use crate::traversal::dist::partition_by;
+use dovahkiin::types::Id;
+
+#[test]
+fn test_partition_by_groups_ids() {
+    let ids = vec![Id::new(0, 1), Id::new(0, 2), Id::new(1, 1)];
+    let parts = partition_by(ids, |id| Some(id.higher));
+    assert_eq!(parts.len(), 2);
+    assert_eq!(parts.get(&0).unwrap().len(), 2);
+    assert_eq!(parts.get(&1).unwrap().len(), 1);
+}