Added mockable HTTPClient for testing

Author: dimitribouniol

Package.swift

@@ -34,7 +34,9 @@ let package = Package(
             ]
         ),
         .testTarget(name: "WebPushTests", dependencies: [
+            .product(name: "AsyncHTTPClient", package: "async-http-client"),
             .product(name: "Logging", package: "swift-log"),
+            .product(name: "NIOCore", package: "swift-nio"),
             .product(name: "ServiceLifecycle", package: "swift-service-lifecycle"),
             .target(name: "WebPush"),
         ]),

Sources/WebPush/Helpers/HTTPClientProtocol.swift

@@ -0,0 +1,23 @@
+//
+//  HTTPClientProtocol.swift
+//  swift-webpush
+//
+//  Created by Dimitri Bouniol on 2024-12-11.
+//  Copyright © 2024 Mochi Development, Inc. All rights reserved.
+//
+
+import AsyncHTTPClient
+import Logging
+import NIOCore
+
+protocol HTTPClientProtocol: Sendable {
+    func execute(
+        _ request: HTTPClientRequest,
+        deadline: NIODeadline,
+        logger: Logger?
+    ) async throws -> HTTPClientResponse
+    
+    func syncShutdown() throws
+}
+
+extension HTTPClient: HTTPClientProtocol {}

Sources/WebPush/WebPushManager.swift

@@ -24,7 +24,7 @@ actor WebPushManager: Sendable {
     public static let maximumMessageSize = maximumEncryptedPayloadSize - 103
 
     nonisolated let logger: Logger
-    let httpClient: HTTPClient
+    var httpClient: any HTTPClientProtocol
 
     let vapidKeyLookup: [VAPID.Key.ID : VAPID.Key]
     var vapidAuthorizationCache: [String : (authorization: String, validUntil: Date)] = [:]
@@ -66,6 +66,13 @@ actor WebPushManager: Sendable {
         }
     }
 
+    /// Internal method to install a different HTTP Client for mocking.
+    ///
+    /// Note that this must be called before ``run()`` is called or the client's syncShutdown won't be called.
+    func installHTTPClient(_ httpClient: HTTPClientProtocol) {
+        self.httpClient = httpClient
+    }
+    
     /// Load an up-to-date Authorization header for the specified endpoint and signing key combo.
     /// - Parameters:
     ///   - endpoint: The endpoint we'll be contacting to send push messages for a given subscriber.
@@ -255,7 +262,7 @@ extension WebPushManager: Service {
         logger.info("Starting up WebPushManager")
         try await withTaskCancellationOrGracefulShutdownHandler {
             try await gracefulShutdown()
-        } onCancelOrGracefulShutdown: { [self] in
+        } onCancelOrGracefulShutdown: { [logger, httpClient] in
             logger.info("Shutting down WebPushManager")
             do {
                 try httpClient.syncShutdown()

Tests/WebPushTests/MockHTTPClient.swift

@@ -0,0 +1,30 @@
+//
+//  MockHTTPClient.swift
+//  swift-webpush
+//
+//  Created by Dimitri Bouniol on 2024-12-11.
+//  Copyright © 2024 Mochi Development, Inc. All rights reserved.
+//
+
+import AsyncHTTPClient
+import Logging
+import NIOCore
+@testable import WebPush
+
+actor MockHTTPClient: HTTPClientProtocol {
+    var processRequest: (HTTPClientRequest) async throws -> HTTPClientResponse
+    
+    init(_ processRequest: @escaping (HTTPClientRequest) async throws -> HTTPClientResponse) {
+        self.processRequest = processRequest
+    }
+    
+    func execute(
+        _ request: HTTPClientRequest,
+        deadline: NIODeadline,
+        logger: Logger?
+    ) async throws -> HTTPClientResponse {
+        try await processRequest(request)
+    }
+    
+    nonisolated func syncShutdown() throws {}
+}