Let feedback effects start immediately. (#21)

* Test cases for immediate observation. * Let feedback effects start immediately. `start(on:)` is not essential for breaking signal recursion.
babylonhealth · Apr 24, 2018 · 1c99379 · 1c99379
1 parent f6b6be1
commit 1c99379
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Showing 3 changed files with 70 additions and 9 deletions.
diff --git a/ReactiveFeedback/Feedback.swift b/ReactiveFeedback/Feedback.swift
@@ -30,7 +30,7 @@ public struct Feedback<State, Event> {
                 .flatMap(.latest) { control -> SignalProducer<Event, NoError> in
                     guard let control = control else { return .empty }
                     return effects(control).producer
-                        .enqueue(on: scheduler)
+                        .observe(on: scheduler)
                 }
         }
     }
@@ -51,7 +51,7 @@ public struct Feedback<State, Event> {
                 .flatMap(.latest) { control -> SignalProducer<Event, NoError> in
                     guard let control = control else { return .empty }
                     return effects(control).producer
-                        .enqueue(on: scheduler)
+                        .observe(on: scheduler)
                 }
         }
     }
@@ -69,7 +69,7 @@ public struct Feedback<State, Event> {
             return state.filter(predicate)
                 .flatMap(.latest) { state -> SignalProducer<Event, NoError> in
                     return effects(state).producer
-                        .enqueue(on: scheduler)
+                        .observe(on: scheduler)
             }
         }
     }
@@ -83,7 +83,7 @@ public struct Feedback<State, Event> {
         self.events = { scheduler, state in
             return state.flatMap(.latest) { state -> SignalProducer<Event, NoError> in
                 return effects(state).producer
-                    .enqueue(on: scheduler)
+                    .observe(on: scheduler)
             }
         }
     }

diff --git a/ReactiveFeedback/SignalProducer+System.swift b/ReactiveFeedback/SignalProducer+System.swift
@@ -56,9 +56,4 @@ extension SignalProducer where Error == NoError {
     private static func deferred(_ producer: @escaping () -> SignalProducer<Value, Error>) -> SignalProducer<Value, Error> {
         return SignalProducer { $1 += producer().start($0) }
     }
-
-    func enqueue(on scheduler: Scheduler) -> SignalProducer<Value, Error> {
-        return producer.start(on: scheduler)
-            .observe(on: scheduler)
-    }
 }
diff --git a/ReactiveFeedbackTests/SystemTests.swift b/ReactiveFeedbackTests/SystemTests.swift
@@ -115,4 +115,70 @@ class SystemTests: XCTestCase {
         ]
         expect(result).toEventually(equal(expected))
     }
+
+    func test_should_observe_signals_immediately() {
+        let scheduler = TestScheduler()
+        let (signal, observer) = Signal<String, NoError>.pipe()
+
+        let system = SignalProducer<String, NoError>.system(
+            initial: "initial",
+            scheduler: scheduler,
+            reduce: { (state: String, event: String) -> String in
+                return state + event
+            },
+            feedbacks: [
+                Feedback { state -> Signal<String, NoError> in
+                    return signal
+                }
+            ]
+        )
+
+        var value: String?
+        system.startWithValues { value = $0 }
+
+        expect(value) == "initial"
+
+        observer.send(value: "_a")
+        expect(value) == "initial"
+
+        scheduler.advance()
+        expect(value) == "initial_a"
+    }
+
+
+    func test_should_start_producers_immediately() {
+        let scheduler = TestScheduler()
+        var startCount = 0
+
+        let system = SignalProducer<String, NoError>.system(
+            initial: "initial",
+            scheduler: scheduler,
+            reduce: { (state: String, event: String) -> String in
+                return state + event
+            },
+            feedbacks: [
+                Feedback { state -> SignalProducer<String, NoError> in
+                    return SignalProducer(value: "_a")
+                        .on(starting: { startCount += 1 })
+                }
+            ]
+        )
+
+        var value: String?
+        system
+            .skipRepeats()
+            .take(first: 2)
+            .startWithValues { value = $0 }
+
+        expect(value) == "initial"
+        expect(startCount) == 1
+
+        scheduler.advance()
+        expect(value) == "initial_a"
+        expect(startCount) == 2
+
+        scheduler.advance()
+        expect(value) == "initial_a"
+        expect(startCount) == 2
+    }
 }