Authors GraphQL subscription resolver test suites over graphql-ws (WebSocket) and graphql-sse (Server-Sent Events) transports: subscribe to event streams via the async-iterator API, assert emitted data shape and sequence, verify connection lifecycle and protocol close codes, and validate auth-on-connect (connectionParams / authenticate callback) plus resolver-level pubsub trigger logic. Use for real-time subscription operations; not for queries or mutations - for those use apollo-server-tests or graphql-yoga-tests (Mercurius in its references).