fix: add completion-based future

Sources/Requests/Receivable/Receivables+Future.swift

@@ -0,0 +1,25 @@
+//
+//  Receivables+Future.swift
+//  ComposableRequest
+//
+//  Created by Stefano Bertagno on 27/08/21.
+//
+
+import Foundation
+
+public extension Receivables {
+    /// A `struct` defining a future receivable.
+    struct Future<Requester: Requests.Requester, Success>: Receivable {
+        /// The completion handler.
+        public let completion: (@escaping (Result<Success, Error>) -> Void) -> Void
+
+        /// Init.
+        ///
+        /// - parameters:
+        ///     - requester: A valid `Requester`.
+        ///     - completion: A valid completion handler.
+        public init(with requester: Requester, _ completion: @escaping (@escaping (Result<Success, Error>) -> Void) -> Void) {
+            self.completion = completion
+        }
+    }
+}

Sources/Requests/Requester/Async/URLSessionAsyncReceivable.swift

@@ -84,6 +84,21 @@ where Parent: URLSessionAsyncReceivable {
     }
 }
 
+@available(iOS 15, macOS 12, watchOS 8, tvOS 15, *)
+extension Receivables.Future: URLSessionAsyncReceivable, URLSessionAsyncMockReceivable
+where Requester.Output: URLSessionAsyncReceivable {
+    // swiftlint:disable empty_parentheses_with_trailing_closure
+    /// The underlying response.
+    public var response: URLSessionAsyncRequester.Response<Success> {
+        .init(priority: nil) {
+            try await withCheckedContinuation { resolve in
+                self.completion() { resolve.resume(returning: $0) }
+            }.get()
+        }
+    }
+    // swiftlint:enable empty_parentheses_with_trailing_closure
+}
+
 @available(iOS 15, macOS 12, watchOS 8, tvOS 15, *)
 extension Receivables.If: URLSessionAsyncReceivable, URLSessionAsyncMockReceivable
 where O1: URLSessionAsyncReceivable, O2: URLSessionAsyncReceivable {

Sources/Requests/Requester/Combine/URLSessionCombineReceivable.swift

@@ -73,6 +73,15 @@ where Parent: URLSessionCombineReceivable {
     }
 }
 
+@available(iOS 13, macOS 10.15, tvOS 13, watchOS 6, *)
+extension Receivables.Future: URLSessionCombineReceivable, URLSessionCombineMockReceivable
+where Requester: URLSessionCombineReceivable {
+    /// The underlying response.
+    public var response: URLSessionCombineRequester.Response<Success> {
+        .init(publisher: Future { resolve in self.completion { resolve($0) } })
+    }
+}
+
 @available(iOS 13, macOS 10.15, tvOS 13, watchOS 6, *)
 extension Receivables.If: URLSessionCombineReceivable, URLSessionCombineMockReceivable
 where O1: URLSessionCombineReceivable, O2: URLSessionCombineReceivable {

Sources/Requests/Requester/Completion/URLSessionCompletionReceivable.swift

@@ -79,6 +79,16 @@ where Parent: URLSessionCompletionReceivable {
     }
 }
 
+extension Receivables.Future: URLSessionCompletionReceivable, URLSessionCompletionMockReceivable
+where Requester.Output: URLSessionCompletionReceivable {
+    /// The response.
+    public var response: URLSessionCompletionRequester.Response<Success> {
+        let promise = Promise<Success, Error>()
+        completion { promise.resolve(result: $0) }
+        return .init(future: promise.future)
+    }
+}
+
 extension Receivables.If: URLSessionCompletionReceivable, URLSessionCompletionMockReceivable
 where O1: URLSessionCompletionReceivable, O2: URLSessionCompletionReceivable {
     /// The response.
@@ -107,7 +117,7 @@ extension Receivables.Once: URLSessionCompletionReceivable, URLSessionCompletion
 where Requester.Output: URLSessionCompletionReceivable {
     /// The response.
     public var response: URLSessionCompletionRequester.Response<Success> {
-        .init(task: nil, future: .init(result: result))
+        .init(future: .init(result: result))
     }
 }