Added support for rotating through multiple mocked message handlers

Author: dimitribouniol

Sources/WebPushTesting/WebPushManager+Testing.swift

@@ -8,12 +8,21 @@
 
 import Logging
 import WebPush
+import Synchronization
 
 extension WebPushManager {
     /// A push message in its original form, either ``/Foundation/Data``, ``/Swift/String``, or ``/Foundation/Encodable``.
     /// - Warning: Never switch on the message type, as values may be added to it over time.
     public typealias Message = _Message
 
+    public typealias MessageHandler = @Sendable (
+        _ message: Message,
+        _ subscriber: Subscriber,
+        _ topic: Topic?,
+        _ expiration: Expiration,
+        _ urgency: Urgency
+    ) async throws -> Void
+    
     /// Create a mocked web push manager.
     ///
     /// The mocked manager will forward all messages as is to its message handler so that you may either verify that a push was sent, or inspect the contents of the message that was sent.
@@ -27,13 +36,7 @@ extension WebPushManager {
         vapidConfiguration: VAPID.Configuration = .mockedConfiguration,
         // TODO: Add networkConfiguration for proxy, number of simultaneous pushes, etc…
         backgroundActivityLogger: Logger? = .defaultWebPushPrintLogger,
-        messageHandler: @escaping @Sendable (
-            _ message: Message,
-            _ subscriber: Subscriber,
-            _ topic: Topic?,
-            _ expiration: Expiration,
-            _ urgency: Urgency
-        ) async throws -> Void
+        messageHandler: @escaping MessageHandler
     ) -> WebPushManager {
         let backgroundActivityLogger = backgroundActivityLogger ?? .defaultWebPushNoOpLogger
 
@@ -43,4 +46,40 @@ extension WebPushManager {
             executor: .handler(messageHandler)
         )
     }
+    
+    /// Create a mocked web push manager.
+    ///
+    /// The mocked manager will forward all messages as is to its message handlers so that you may either verify that a push was sent, or inspect the contents of the message that was sent. Assign multiple handlers here to have each message that comes in rotate through the handlers, looping when they are exausted.
+    ///
+    /// - Parameters:
+    ///   - vapidConfiguration: A VAPID configuration, though the mocked manager doesn't make use of it.
+    ///   - logger: An optional logger.
+    ///   - messageHandlers: A list of handlers to receive messages or throw errors.
+    /// - Returns: A new manager suitable for mocking.
+    @available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
+    @_disfavoredOverload
+    public static func makeMockedManager(
+        vapidConfiguration: VAPID.Configuration = .mockedConfiguration,
+        // TODO: Add networkConfiguration for proxy, number of simultaneous pushes, etc…
+        backgroundActivityLogger: Logger? = .defaultWebPushPrintLogger,
+        messageHandlers: @escaping MessageHandler,
+        _ otherHandlers: MessageHandler...
+    ) -> WebPushManager {
+        let backgroundActivityLogger = backgroundActivityLogger ?? .defaultWebPushNoOpLogger
+        let index = Mutex(0)
+        let allHandlers = [messageHandlers] + otherHandlers
+        
+        return WebPushManager(
+            vapidConfiguration: vapidConfiguration,
+            backgroundActivityLogger: backgroundActivityLogger,
+            executor: .handler({ message, subscriber, topic, expiration, urgency in
+                let currentIndex = index.withLock { index in
+                    let current = index
+                    index = (index + 1) % allHandlers.count
+                    return current
+                }
+                return try await allHandlers[currentIndex](message, subscriber, topic, expiration, urgency)
+            })
+        )
+    }
 }

Tests/WebPushTests/WebPushManagerTests.swift

@@ -878,18 +878,28 @@ struct WebPushManagerTests {
             }
         }
 
+        @available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
         @Test func sendPropagatedMockedFailure() async throws {
-            await confirmation { requestWasMade in
-                struct CustomError: Error {}
-                
-                let manager = WebPushManager.makeMockedManager(backgroundActivityLogger: Logger(label: "WebPushManagerTests", factory: { PrintLogHandler(label: $0, metadataProvider: $1) })) { _, _, _, _, _ in
-                    requestWasMade()
-                    throw CustomError()
-                }
-                
-                await #expect(throws: CustomError.self) {
-                    try await manager.send(data: Array(repeating: 0, count: 3994), to: .mockedSubscriber())
-                }
+            struct CustomError: Error {}
+            
+            let manager = WebPushManager.makeMockedManager(
+                backgroundActivityLogger: nil,
+                messageHandlers:
+                    { _, _, _, _, _ in throw BadSubscriberError() },
+                    { _, _, _, _, _ in throw CustomError() }
+            )
+            
+            await #expect(throws: BadSubscriberError.self) {
+                try await manager.send(string: "test", to: .mockedSubscriber())
+            }
+            await #expect(throws: CustomError.self) {
+                try await manager.send(string: "test", to: .mockedSubscriber())
+            }
+            await #expect(throws: BadSubscriberError.self) {
+                try await manager.send(string: "test", to: .mockedSubscriber())
+            }
+            await #expect(throws: CustomError.self) {
+                try await manager.send(string: "test", to: .mockedSubscriber())
             }
         }
     }