Prepare isExpired to pass a margin for slower scenarios (#20)

* move to 250ms for slow suscriptions

* Move margin to variable and set default value to 250ms

* Bump dependencies

* Fix CI

* Try with margin

* Pass margin to isExpired too

Author: sebastianvarela

Sources/Publishers/Publishers.RemoveExpired.swift

@@ -1,9 +1,9 @@
 import Combine
 
 public extension Publisher {
-    func removeExpired() -> Publishers.RemoveExpired<Self>
+    func removeExpired(margin: TimeInterval = taskDefaultMargin) -> Publishers.RemoveExpired<Self>
     where Output: Taskable {
-        Publishers.RemoveExpired(upstream: self)
+        Publishers.RemoveExpired(upstream: self, margin: margin)
     }
 }
 
@@ -15,13 +15,15 @@ public extension Publishers {
         public typealias Failure = Upstream.Failure
 
         public let upstream: Upstream
+        private let margin: TimeInterval
 
-        public init(upstream: Upstream) {
+        public init(upstream: Upstream, margin: TimeInterval) {
             self.upstream = upstream
+            self.margin = margin
         }
 
         public func receive<S: Subscriber>(subscriber: S) where Upstream.Failure == S.Failure, Output == S.Input {
-            upstream.subscribe(Inner(downstream: subscriber))
+            upstream.subscribe(Inner(downstream: subscriber, margin: margin))
         }
     }
 }
@@ -31,17 +33,19 @@ extension Publishers.RemoveExpired {
     where Downstream.Input == Output, Downstream.Failure == Upstream.Failure, Output: Taskable {
         let combineIdentifier = CombineIdentifier()
         private let downstream: Downstream
+        private let margin: TimeInterval
 
-        fileprivate init(downstream: Downstream) {
+        fileprivate init(downstream: Downstream, margin: TimeInterval) {
             self.downstream = downstream
+            self.margin = margin
         }
 
         func receive(subscription: Subscription) {
             downstream.receive(subscription: subscription)
         }
 
         func receive(_ input: Upstream.Output) -> Subscribers.Demand {
-            if input.isExpired {
+            if input.isExpired(margin: margin) {
                 return .none
             }
             return downstream.receive(input)

Sources/Publishers/Publishers.Scope.swift

@@ -3,9 +3,9 @@ import Foundation
 
 public extension Publisher {
     /// From a publisher, we can focus on a task and filter all expired and duplicated task. This publisher don't send value if at suscription moment there is a expired task.
-    func scope<T: Taskable & Equatable>(_ transform: @escaping (Self.Output) -> T) -> AnyPublisher<T, Failure> {
+    func scope<T: Taskable & Equatable>(_ transform: @escaping (Self.Output) -> T, margin: TimeInterval = taskDefaultMargin) -> AnyPublisher<T, Failure> {
         map(transform)
-            .removeExpired()
+            .removeExpired(margin: margin)
             .removeDuplicates()
             .eraseToAnyPublisher()
     }

Sources/Task/Task.swift

@@ -1,5 +1,7 @@
 import Foundation
 
+public let taskDefaultMargin: TimeInterval = 0.250
+
 public class Task<T: Equatable, E: Error & Equatable>: Taskable, Equatable, CustomDebugStringConvertible {
     public typealias Payload = T
     public typealias Failure = E
@@ -50,9 +52,8 @@ public class Task<T: Equatable, E: Error & Equatable>: Taskable, Equatable, Cust
         status == .running
     }
 
-    public var isExpired: Bool {
-        let margin: TimeInterval = 0.1 // 100ms for suscriptions propagations
-        return started.timeIntervalSinceNow + expiration.value + margin < 0
+    public func isExpired(margin: TimeInterval) -> Bool {
+        started.timeIntervalSinceNow + expiration.value + margin < 0
     }
 
     public var isRecentlySucceeded: Bool {

Sources/Task/Taskable.swift

@@ -6,7 +6,7 @@ public protocol Taskable {
 
     var isIdle: Bool { get }
     var isRunning: Bool { get }
-    var isExpired: Bool { get }
+    func isExpired(margin: TimeInterval) -> Bool
     var isRecentlySucceeded: Bool { get }
     var isTerminal: Bool { get }
     var isSuccessful: Bool { get }
@@ -23,6 +23,12 @@ public protocol Taskable {
     static func success(_ payload: Payload, started: Date, expiration: TaskExpiration, tag: String?, progress: Decimal?) -> Self
 }
 
+public extension Taskable {
+    var isExpired: Bool {
+        self.isExpired(margin: taskDefaultMargin)
+    }
+}
+
 public extension Taskable {
     static func idle(started: Date = Date(),
                      tag: String? = nil,

Tests/PublishersTests+RemoveExpired.swift

@@ -10,11 +10,13 @@ extension PublishersTests {
 
         let subject = PassthroughSubject<Task<String, TestError>, Never>()
 
+        let margin: TimeInterval = 0.500
+
         subject
-            .removeExpired() // Filter the 2 expired task
+            .removeExpired(margin: margin) // Filter the 2 expired task
             .removeDuplicates() // Pass only the first success task because the expired they never get here!
             .sink { task in
-                XCTAssertFalse(task.isExpired)
+                XCTAssertFalse(task.isExpired(margin: margin))
                 expectation.fulfill()
             }
             .store(in: &cancellables)