AnyPublisher extensions for Just, Fail and Empty

Sources/Convenience/AnyPublisher.swift

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+//
+//  AnyPublisher.swift
+//  CombineExt
+//
+//  Created by Stefano Mondino on 14/04/23.
+//  Copyright © 2020 Combine Community. All rights reserved.
+//
+
+#if canImport(Combine)
+import Combine
+
+@available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+public extension AnyPublisher {
+    /// A wrapper around a type erased Just
+    static func just(_ value: Output) -> AnyPublisher<Output, Failure> {
+        Just(value)
+            .setFailureType(to: Failure.self)
+            .eraseToAnyPublisher()
+    }
+
+    /// A wrapper around a type erased Empty
+    static func empty() -> AnyPublisher<Output, Failure> {
+        Empty()
+            .setFailureType(to: Failure.self)
+            .eraseToAnyPublisher()
+    }
+
+    /// A wrapper around a type erased Fail
+    static func fail(error: Failure) -> AnyPublisher<Output, Failure> {
+        Fail(error: error).eraseToAnyPublisher()
+    }
+}
+#endif

Tests/AnyPublisherTests.swift

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+//
+//  OptionalTests.swift
+//  CombineExt
+//
+//  Created by Jasdev Singh on 11/05/2020.
+//  Copyright © 2020 Combine Community. All rights reserved.
+//
+
+#if !os(watchOS)
+import Combine
+import CombineExt
+import XCTest
+
+@available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+final class AnyPublisherTests: XCTestCase {
+    private var subscription: AnyCancellable!
+
+    func testJustInitialization() {
+        var results = [Int]()
+        var completion: Subscribers.Completion<Never>?
+
+        subscription = AnyPublisher.just(1)
+
+            .sink(receiveCompletion: { completion = $0 },
+                  receiveValue: { results.append($0) })
+
+        XCTAssertEqual([1], results)
+        XCTAssertEqual(.finished, completion)
+    }
+
+    func testEmptyInitialization() {
+        var results = [Int]()
+        var completion: Subscribers.Completion<Never>?
+
+        subscription = AnyPublisher<Int, Never>.empty()
+            .sink(receiveCompletion: { completion = $0 }, receiveValue: { results.append($0) })
+
+        XCTAssertEqual([], results)
+        XCTAssertEqual(.finished, completion)
+    }
+
+    func testFailInitialization() {
+        enum CustomError: Swift.Error {
+            case someError
+        }
+        var results = [Int]()
+        var completion: Subscribers.Completion<CustomError>?
+
+        subscription = AnyPublisher<Int, CustomError>.fail(error: .someError)
+            .sink(receiveCompletion: { completion = $0 }, receiveValue: { results.append($0) })
+
+        XCTAssertEqual([], results)
+        XCTAssertEqual(.failure(.someError), completion)
+    }
+
+}
+#endif