Write some basic test utils to get going; time to start trying them

backend/test_utils/src/lib.rs

@@ -1,3 +1,8 @@
+// A helper to spawn or connect to shard/core processes and hand back connections to them
+pub mod connect_to_servers;
+
 /// A wrapper around soketto to simplify the process of establishing connections
 pub mod ws_client;
-pub mod connect_to_servers;
+
+/// A helper to construct simple test cases involving a single shard and feed.
+pub mod test_simple;