test: add test with ioredis and Redis cluster (#570)

Support for sharded pub/sub was added in `ioredis@5.9.0`.

Related:

- redis/ioredis#1759
- redis/ioredis#1956

Author: seta-chuang-0909

README.md

@@ -18,6 +18,8 @@ The `@socket.io/redis-adapter` package allows broadcasting packets between multi
   - [With the `ioredis` package](#with-the-ioredis-package)
   - [With the `ioredis` package and a Redis cluster](#with-the-ioredis-package-and-a-redis-cluster)
   - [With Redis sharded Pub/Sub](#with-redis-sharded-pubsub)
+    - [With `redis`](#with-redis)
+    - [With `ioredis`](#with-ioredis)
 - [Options](#options)
   - [Default adapter](#default-adapter)
   - [Sharded adapter](#sharded-adapter)
@@ -161,6 +163,13 @@ Reference: https://redis.io/docs/interact/pubsub/#sharded-pubsub
 
 A dedicated adapter can be created with the `createShardedAdapter()` method:
 
+#### With `redis`
+
+Minimum requirements:
+
+- Redis 7.0
+- [`redis@4.6.0`](https://github.com/redis/node-redis/commit/3b1bad229674b421b2bc6424155b20d4d3e45bd1)
+
 ```js
 import { Server } from "socket.io";
 import { createClient } from "redis";
@@ -181,12 +190,47 @@ const io = new Server({
 io.listen(3000);
 ```
 
+#### With `ioredis`
+
 Minimum requirements:
 
 - Redis 7.0
-- [`redis@4.6.0`](https://github.com/redis/node-redis/commit/3b1bad229674b421b2bc6424155b20d4d3e45bd1)
+- [`ioredis@5.9.0`](https://github.com/redis/ioredis/pull/1956)
+
+Please note that the `shardedSubscribers` option is required to enable sharded Pub/Sub.
+
+```js
+import { Cluster } from "ioredis";
+import { Server } from "socket.io";
+import { createShardedAdapter } from "@socket.io/redis-adapter";
+
+const pubClient = new Cluster(
+  [
+    {
+      host: "localhost",
+      port: 7000,
+    },
+    {
+      host: "localhost",
+      port: 7001,
+    },
+    {
+      host: "localhost",
+      port: 7002,
+    },
+  ],
+  {
+    shardedSubscribers: true,
+  }
+);
+const subClient = pubClient.duplicate();
 
-Note: it is not currently possible to use the sharded adapter with the `ioredis` package and a Redis cluster ([reference](https://github.com/luin/ioredis/issues/1759)).
+const io = new Server({
+  adapter: createShardedAdapter(pubClient, subClient)
+});
+
+io.listen(3000);
+```
 
 ## Options
 

package-lock.json

@@ -32,7 +32,7 @@
     "@types/mocha": "^8.2.1",
     "@types/node": "^14.14.7",
     "expect.js": "0.3.1",
-    "ioredis": "^5.3.2",
+    "ioredis": "^5.9.1",
     "mocha": "^10.1.0",
     "nyc": "^15.1.0",
     "prettier": "^2.8.7",

package.json

@@ -259,11 +259,12 @@ describe("@socket.io/redis-adapter", () => {
       true
     ));
 
-  // FIXME see https://github.com/luin/ioredis/issues/1759
-  describe.skip("[sharded] ioredis cluster", () =>
+  describe("[sharded] ioredis cluster", () =>
     testSuite(
       async () => {
-        const pubClient = new Cluster(clusterNodes);
+        const pubClient = new Cluster(clusterNodes, {
+          shardedSubscribers: true,
+        });
         const subClient = pubClient.duplicate();
 
         return [