Fix pubsub channels

Author: PeterAdams-A

Sources/RediStack/Commands/PubSubCommands.swift

@@ -37,8 +37,11 @@ extension RedisCommand {
     /// - Invariant: If no `match` pattern is provided, all active channels will be returned.
     /// - Parameter match: An optional pattern of channel names to filter for.
     public static func pubsubChannels(matching match: String? = nil) -> RedisCommand<[RedisChannelName]> {
-        let args: [RESPValue] = match.map { [.init(bulk: $0)] } ?? []
-        return .init(keyword: "PUBSUB CHANNELS", arguments: args)
+        var args: [RESPValue] = [.init(bulk: "CHANNELS")]
+        if let match = match {
+            args.append(.init(bulk: match))
+        }
+        return .init(keyword: "PUBSUB", arguments: args)
     }
 
     /// [PUBSUB NUMPAT](https://redis.io/commands/pubsub#codepubsub-numpatcode)

Tests/RediStackIntegrationTests/Commands/PubSubCommandsTests.swift

@@ -189,6 +189,41 @@ final class RedisPubSubCommandsTests: RediStackIntegrationTestCase {
 
         self.waitForExpectations(timeout: 1)
     }
+
+    func test_pubSubChannels() throws {
+        let fn = #function
+        let subscriber = try self.makeNewConnection()
+        defer { try? subscriber.close().wait() }
+
+        let channelNames = (1...10).map {
+            RedisChannelName("\(fn)\($0)\($0 % 2 == 0 ? "_even" : "_odd")")
+        }
+
+        for channelName in channelNames {
+            try subscriber.subscribe(
+                to: channelName,
+                messageReceiver: { _, _ in },
+                onSubscribe: nil,
+                onUnsubscribe: nil
+            ).wait()
+        }
+        XCTAssertTrue(subscriber.isSubscribed)
+        defer {
+            // Unsubscribe (clean up)
+            try? subscriber.unsubscribe(from: channelNames).wait()
+            XCTAssertFalse(subscriber.isSubscribed)
+        }
+
+        // Make another connection to query on.
+        let queryConnection = try self.makeNewConnection()
+        defer { try? queryConnection.close().wait() }
+
+        let oddChannels = try queryConnection.send(.pubsubChannels(matching: "\(fn)*_odd")).wait()
+        XCTAssertEqual(oddChannels.count, channelNames.count / 2)
+
+        let allChannels = try queryConnection.send(.pubsubChannels()).wait()
+        XCTAssertGreaterThanOrEqual(allChannels.count, channelNames.count)
+    }
 }
 
 final class RedisPubSubCommandsPoolTests: RediStackConnectionPoolIntegrationTestCase {