test: add sharded pub/sub cases (#179)

Author: supercaracal

test/redis_client/test_cluster.rb

@@ -168,7 +168,7 @@ def test_pipelined_with_many_commands
         results.each_with_index { |got, i| assert_equal(i.to_s, got) }
       end
 
-      def test_pubsub
+      def test_global_pubsub
         10.times do |i|
           pubsub = @client.pubsub
           pubsub.call('SUBSCRIBE', "channel#{i}")
@@ -189,6 +189,28 @@ def test_pubsub
         assert_equal(['message', channel, 'hello world'], sub.resume)
       end
 
+      def test_sharded_pubsub
+        if TEST_REDIS_MAJOR_VERSION < 7
+          skip('Sharded Pub/Sub is supported by Redis 7+.')
+          return
+        end
+
+        10.times do |i|
+          sub = Fiber.new do |client|
+            channel = "my-channel-#{i}"
+            pubsub = client.pubsub
+            pubsub.call('SSUBSCRIBE', channel)
+            assert_equal(['ssubscribe', channel, 1], pubsub.next_event(TEST_TIMEOUT_SEC))
+            Fiber.yield(channel)
+            Fiber.yield(pubsub.next_event(TEST_TIMEOUT_SEC))
+          end
+
+          channel = sub.resume(@client)
+          @client.call('SPUBLISH', channel, "hello world #{i}")
+          assert_equal(['smessage', channel, "hello world #{i}"], sub.resume)
+        end
+      end
+
       def test_close
         assert_nil(@client.close)
       end