Implemented the Auth middleware (#3)

This PR contains the work done to implement the `AuthMiddleware` middleware that, when plugged into a `Client` object, adds authentication parameters to any request the client would make.

Reviewed-on: #3
Co-authored-by: Javier Cicchelli <javier@rock-n-code.com>
Co-committed-by: Javier Cicchelli <javier@rock-n-code.com>

Tests/MarvelService/Cases/Internal/Extensions/TimeInterval+ComputedTests.swift

@@ -0,0 +1,90 @@
+//===----------------------------------------------------------------------===
+//
+// This source file is part of the MarvelService open source project
+//
+// Copyright (c) 2025 Röck+Cöde VoF. and the MarvelService project authors
+// Licensed under the EUPL 1.2 or later.
+//
+// See LICENSE for license information
+// See CONTRIBUTORS for the list of MarvelService project authors
+//
+//===----------------------------------------------------------------------===
+
+import Testing
+
+import struct Foundation.TimeInterval
+
+@testable import MarvelService
+
+@Suite("Time Interval computed properties", .tags(.extension))
+struct TimeIntervalComputedTests {
+    
+    // MARK: Properties tests
+    
+#if swift(>=6.2)
+    @Test(arguments: zip(
+        Input.timestamps,
+        Output.timestampAsString
+    ))
+    func `asString`(
+        timestamp: TimeInterval,
+        expects string: String
+    ) {
+        assertAsString(
+            timestamp: timestamp,
+            expects: string
+        )
+    }
+#else
+    @Test("asString", arguments: zip(
+        Input.timestamps,
+        Output.timestampAsString
+    ))
+    func asString(
+        timestamp: TimeInterval,
+        expects string: String
+    ) {
+        assertAsString(
+            timestamp: timestamp,
+            expects: string
+        )
+    }
+#endif
+    
+}
+
+// MARK: - Assertions
+
+private extension TimeIntervalComputedTests {
+    
+    // MARK: Functions
+    
+    /// Asserts the timestamp to string conversion.
+    /// - Parameters:
+    ///   - timestamp: A timestamp to convert.
+    ///   - string: An expected timestamp converted to string.
+    func assertAsString(
+        timestamp: TimeInterval,
+        expects string: String
+    ) {
+        // GIVEN
+        // WHEN
+        let result = timestamp.asString
+        
+        // THEN
+        #expect(result == string)
+    }
+
+}
+
+// MARK: - Constants
+
+private extension Output {
+    /// A list of outcomes that are expected from converting timestamps to string.
+    static let timestampAsString: [String] = [
+        "0.000000",
+        "1000.000000",
+        "1000000.000000",
+        "1000000000.000000"
+    ]
+}

Tests/MarvelService/Cases/Internal/Use Cases/GenerateHashUseCaseTests.swift

@@ -0,0 +1,95 @@
+//===----------------------------------------------------------------------===
+//
+// This source file is part of the MarvelService open source project
+//
+// Copyright (c) 2025 Röck+Cöde VoF. and the MarvelService project authors
+// Licensed under the EUPL 1.2 or later.
+//
+// See LICENSE for license information
+// See CONTRIBUTORS for the list of MarvelService project authors
+//
+//===----------------------------------------------------------------------===
+
+import Testing
+
+import struct Foundation.TimeInterval
+
+@testable import struct MarvelService.GenerateHashUseCase
+
+@Suite("Generate Hash Use Case", .tags(.useCase))
+struct GenerateHashUseCaseTests {
+    
+    // MARK: Functions
+    
+#if swift(>=6.2)
+    @Test(arguments: zip(
+        Input.timestamps,
+        Output.generatedHashes
+    ))
+    func `hash`(
+        timestamp: TimeInterval,
+        expects hash: String
+    ) async throws {
+        assertHash(
+            timestamp: timestamp,
+            expects: hash
+        )
+    }
+#else
+    @Test("hash", arguments: zip(
+        Input.timestamps,
+        Output.generatedHashes
+    ))
+    func hash(
+        timestamp: TimeInterval,
+        expects hash: String
+    ) async throws {
+        assertHash(
+            timestamp: timestamp,
+            expects: hash
+        )
+    }
+#endif
+    
+}
+
+// MARK: - Assertions
+
+private extension GenerateHashUseCaseTests {
+   
+    // MARK: Functions
+    
+    /// Asserts the MD5 hash generated from the use case.
+    /// - Parameters:
+    ///   - timestamp: A timestamp to use in the hash generation.
+    ///   - hash: An expected MD5 hash string as a result of the use case.
+    func assertHash(
+        timestamp: TimeInterval,
+        expects hash: String
+    ) {
+        // GIVEN
+        let useCase: GenerateHashUseCase = .init(
+            privateKey: .Key.private,
+            publicKey: .Key.public
+        )
+
+        // WHEN
+        let result = useCase(timestamp: timestamp)
+
+        // THEN
+        #expect(result == hash)
+    }
+    
+}
+
+// MARK: - Constants
+
+private extension Output {
+    /// A list of outcomes that are expected from the hash generation.
+    static let generatedHashes: [String] = [
+        "ef9ca6f930e56fb4f8a109a9003580fe",
+        "b500748e9f0aabc67ffc640ae9b87695",
+        "b537f18579112902b7ce046dddad558a",
+        "00fec88a254d42e3a439d49e14cd60d1"
+    ]
+}

Tests/MarvelService/Cases/Public/Middlewares/AuthMiddlewareTests.swift

@@ -0,0 +1,135 @@
+//===----------------------------------------------------------------------===
+//
+// This source file is part of the MarvelService open source project
+//
+// Copyright (c) 2025 Röck+Cöde VoF. and the MarvelService project authors
+// Licensed under the EUPL 1.2 or later.
+//
+// See LICENSE for license information
+// See CONTRIBUTORS for the list of MarvelService project authors
+//
+//===----------------------------------------------------------------------===
+
+import Testing
+
+import struct Foundation.URL
+import struct Foundation.URLComponents
+import struct HTTPTypes.HTTPRequest
+import struct HTTPTypes.HTTPResponse
+import struct MarvelService.AuthMiddleware
+
+@Suite("Auth Middleware", .tags(.middleware))
+struct AuthMiddlewareTest {
+    
+    // MARK: Functions
+    
+#if swift(>=6.2)
+    @Test(arguments: Input.pathRequests)
+    func `intercept`(path: String?) async throws {
+        try await assertIntercept(path: path)
+    }
+#else
+    @Test("intercept", arguments: Input.pathRequests)
+    func intercept(path: String?) async throws {
+        try await assertIntercept(path: path)
+    }
+#endif
+    
+}
+
+// MARK: - Assertions
+
+private extension AuthMiddlewareTest {
+    
+    // MARK: Functions
+    
+    /// Asserts the interception of a request to add authentication parameters in it.
+    /// - Parameter path: A URI path for a request.
+    /// - Throws: An error in case
+    func assertIntercept(path: String?) async throws {
+        // GIVEN
+        let baseURL: URL = .baseURL
+        let request: HTTPRequest = .init(path: path)
+        
+        let middleware: AuthMiddleware = .init(
+            privateKey: .Key.private,
+            publicKey: .Key.public
+        )
+        
+        // WHEN
+        _ = try await confirmation { confirmation in
+            try await middleware.intercept(
+                request,
+                body: nil,
+                baseURL: baseURL,
+                operationID: .operationId
+            ) { request, _, _ in
+                // THEN
+                if path != nil {
+                    let pathRequest = try #require(request.path)
+                    let urlComponents = try #require(URLComponents(string: pathRequest))
+                    let queryItems = try #require(urlComponents.queryItems)
+                    
+                    #expect(queryItems.count >= 3)
+                    #expect(queryItems.contains(where: { $0.name == "ts" }))
+                    #expect(queryItems.contains(where: { $0.name == "apikey" }))
+                    #expect(queryItems.contains(where: { $0.name == "hash" }))
+                } else {
+                    #expect(request.path == nil)
+                }
+
+                confirmation()
+                
+                return (.init(status: .ok) , nil)
+            }
+        }
+    }
+    
+}
+
+// MARK: - Helpers
+
+private extension HTTPRequest {
+    
+    // MARK: Initializers
+    
+    /// Initializes a HTTP request with a method and a path.
+    /// - Parameters:
+    ///   - method: The request method.
+    ///   - path: The value of the “:path” pseudo header field.
+    init(
+        method: HTTPRequest.Method = .get,
+        path: String?
+    ) {
+        self.init(
+            method: method,
+            scheme: nil,
+            authority: nil,
+            path: path
+        )
+    }
+
+}
+
+// MARK: - Constants
+
+private extension Input {
+    /// A list of URI path to a resource for a request.
+    static let pathRequests: [String?] = [
+        nil,
+        "/path/to/resource",
+        "/path/to/resource?boolean",
+        "/path/to/resource?query=value",
+        "/path/to/resource?query=value&anotherQuery=anotherValue"
+    ]
+}
+
+private extension String {
+    /// An operation ID sample.
+    static let operationId = "SomeOperationId"
+}
+
+private extension URL {
+    /// A base URL sample.
+    static let baseURL = URL(string: "https://sample.domain.com")!
+}

Tests/MarvelService/Types/Extensions/String+Samples.swift

@@ -0,0 +1,21 @@
+//===----------------------------------------------------------------------===
+//
+// This source file is part of the MarvelService open source project
+//
+// Copyright (c) 2025 Röck+Cöde VoF. and the MarvelService project authors
+// Licensed under the EUPL 1.2 or later.
+//
+// See LICENSE for license information
+// See CONTRIBUTORS for the list of MarvelService project authors
+//
+//===----------------------------------------------------------------------===
+
+extension String {
+    /// A namespace assigned for Marvel API key samples.
+    enum Key {
+        /// A Marvel API private key sample.
+        static let `private` = "SomePrivateKey"
+        /// A Marvel API public key sample.
+        static let `public` = "SomePublicKey"
+    }
+}

Tests/MarvelService/Types/Extensions/Tag+Customs.swift

@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===
+//
+// This source file is part of the MarvelService open source project
+//
+// Copyright (c) 2025 Röck+Cöde VoF. and the MarvelService project authors
+// Licensed under the EUPL 1.2 or later.
+//
+// See LICENSE for license information
+// See CONTRIBUTORS for the list of MarvelService project authors
+//
+//===----------------------------------------------------------------------===
+
+import Testing
+
+extension Tag {
+    
+    // MARK: Constants
+    
+    /// A flag that indicates tests for a type extension.
+    @Tag static var `extension`: Self
+    
+    /// A flag that indicates tests for a middleware type.
+    @Tag static var middleware: Self
+    
+    /// A flag that indicates tests for a use case type.
+    @Tag static var useCase: Self
+}

Tests/MarvelService/Types/Namespaces/Input.swift

@@ -0,0 +1,28 @@
+//===----------------------------------------------------------------------===
+//
+// This source file is part of the MarvelService open source project
+//
+// Copyright (c) 2025 Röck+Cöde VoF. and the MarvelService project authors
+// Licensed under the EUPL 1.2 or later.
+//
+// See LICENSE for license information
+// See CONTRIBUTORS for the list of MarvelService project authors
+//
+//===----------------------------------------------------------------------===
+
+import struct Foundation.Date
+import struct Foundation.TimeInterval
+
+/// A namespace assigned for input arguments on test cases.
+enum Input {
+    
+    // MARK: Constants
+
+    /// A list of timestamps samples.
+    static let timestamps: [TimeInterval] = [
+        Date(timeIntervalSince1970: 0).timeIntervalSince1970,
+        Date(timeIntervalSince1970: 1_000).timeIntervalSince1970,
+        Date(timeIntervalSince1970: 1_000_000).timeIntervalSince1970,
+        Date(timeIntervalSince1970: 1_000_000_000).timeIntervalSince1970,
+    ]
+}

Tests/MarvelService/Types/Namespaces/Output.swift

@@ -0,0 +1,14 @@
+//===----------------------------------------------------------------------===
+//
+// This source file is part of the MarvelService open source project
+//
+// Copyright (c) 2025 Röck+Cöde VoF. and the MarvelService project authors
+// Licensed under the EUPL 1.2 or later.
+//
+// See LICENSE for license information
+// See CONTRIBUTORS for the list of MarvelService project authors
+//
+//===----------------------------------------------------------------------===
+
+/// A namespace assigned for output arguments on test cases, that are expected results.
+enum Output {}