Add testUnsubscribeFromOneChannel

Author: adam-fowler

Tests/ValkeyTests/ValkeySubscriptionTests.swift

@@ -80,6 +80,7 @@ struct SubscriptionTests {
         }
     }
 
+    /// Test a single subscription can subscribe to multiple channels
     @Test
     func testSubscribeMultipleChannels() async throws {
         let channel = NIOAsyncTestingChannel()
@@ -111,6 +112,45 @@ struct SubscriptionTests {
         }
     }
 
+    /// Test when unsubscribing from one channel, that you will still receive messages from other channels you are
+    /// still subscribed to
+    @Test
+    func testUnsubscribeFromOneChannel() async throws {
+        let channel = NIOAsyncTestingChannel()
+        let logger = Logger(label: "test")
+        let connection = try await ValkeyConnection.setupChannel(channel, configuration: .init(), logger: logger)
+
+        try await withThrowingTaskGroup(of: Void.self) { group in
+            group.addTask {
+                let subscription = try await connection.subscribe(to: "test1", "test2", "test3")
+                _ = try await connection.unsubscribe(channel: ["test2"])
+                var iterator = subscription.makeAsyncIterator()
+                #expect(try await iterator.next() == .init(channel: "test1", message: "1"))
+                #expect(try await iterator.next() == .init(channel: "test3", message: "3"))
+            }
+            group.addTask {
+                var outbound = try await channel.waitForOutboundWrite(as: ByteBuffer.self)
+                // expect SUBSCRIBE command
+                #expect(String(buffer: outbound) == "*4\r\n$9\r\nSUBSCRIBE\r\n$5\r\ntest1\r\n$5\r\ntest2\r\n$5\r\ntest3\r\n")
+                // push 3 subscribes (one for each channel)
+                try await channel.writeInbound(ByteBuffer(string: ">3\r\n$9\r\nsubscribe\r\n$5\r\ntest1\r\n:1\r\n"))
+                try await channel.writeInbound(ByteBuffer(string: ">3\r\n$9\r\nsubscribe\r\n$5\r\ntest2\r\n:2\r\n"))
+                try await channel.writeInbound(ByteBuffer(string: ">3\r\n$9\r\nsubscribe\r\n$5\r\ntest3\r\n:3\r\n"))
+                outbound = try await channel.waitForOutboundWrite(as: ByteBuffer.self)
+                // expect UNSUBSCRIBE command
+                #expect(String(buffer: outbound) == "*2\r\n$11\r\nUNSUBSCRIBE\r\n$5\r\ntest2\r\n")
+                // push unsubscribe
+                try await channel.writeInbound(ByteBuffer(string: ">3\r\n$11\r\nunsubscribe\r\n$5\r\ntest2\r\n:0\r\n"))
+                // push 3 messages
+                try await channel.writeInbound(ByteBuffer(string: ">3\r\n$7\r\nmessage\r\n$5\r\ntest1\r\n$1\r\n1\r\n"))
+                try await channel.writeInbound(ByteBuffer(string: ">3\r\n$7\r\nmessage\r\n$5\r\ntest2\r\n$1\r\n2\r\n"))
+                try await channel.writeInbound(ByteBuffer(string: ">3\r\n$7\r\nmessage\r\n$5\r\ntest3\r\n$1\r\n3\r\n"))
+            }
+            try await group.waitForAll()
+        }
+    }
+
+    /// Test you can have multiple subscriptions running on one connection
     @Test
     func testMultipleSubscriptions() async throws {
         let channel = NIOAsyncTestingChannel()