fix TestScheduler repeating actions

Author: tcldr

.swiftpm/xcode/xcshareddata/xcschemes/EntwineTest.xcscheme

@@ -42,6 +42,16 @@
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "EntwineTestTests"
+               BuildableName = "EntwineTestTests"
+               BlueprintName = "EntwineTestTests"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </TestableReference>
       </Testables>
    </TestAction>
    <LaunchAction

Sources/EntwineTest/TestScheduler/TestScheduler.swift

@@ -56,13 +56,19 @@ public class TestScheduler {
     }
 
     private var currentTime = VirtualTime(0)
+    private let maxTime: VirtualTime
     private var lastTaskId = -1
     private var schedulerQueue: PriorityQueue<TestSchedulerTask>
 
     /// Initialises the scheduler with the given commencement time
-    public init(initialClock: VirtualTime = 0) {
+    ///
+    /// - Parameters:
+    ///   - initialClock: The VirtualTime at which the scheduler will start
+    ///   - maxClock: The VirtualTime ceiling after which the scheduler will cease to process tasks
+    public init(initialClock: VirtualTime = 0, maxClock: VirtualTime = 100_000) {
         self.schedulerQueue = PriorityQueue(ascending: true, startingValues: [])
         self.currentTime = initialClock
+        self.maxTime = maxClock
     }
 
     /// Schedules the creation and subscription of an arbitrary `Publisher` to a `TestableSubscriber`, and
@@ -149,11 +155,27 @@ public class TestScheduler {
     /// more actions remain.
     public func resume() {
         while let next = findNext() {
+            guard next.time <= maxTime else {
+                print("""
+                ⚠️ TestScheduler maxClock (\(maxTime)) reached. Scheduler aborted with \(schedulerQueue.count) remaining tasks.
+                """)
+                break
+            }
             if next.time > currentTime {
                 currentTime = next.time
             }
-            next.action()
             schedulerQueue.remove(next)
+            if next.interval > 0 {
+                schedulerQueue.push(
+                    .init(
+                        id: next.id,
+                        time: now + max(minimumTolerance, next.interval),
+                        interval: next.interval,
+                        action: next.action
+                    )
+                )
+            }
+            next.action()
         }
     }
 
@@ -185,15 +207,18 @@ extension TestScheduler: Scheduler {
     public var minimumTolerance: VirtualTimeInterval { 1 }
 
     public func schedule(options: Never?, _ action: @escaping () -> Void) {
-        schedulerQueue.push(TestSchedulerTask(id: nextTaskId(), time: currentTime, action: action))
+        schedulerQueue.push(
+            TestSchedulerTask(id: nextTaskId(), time: currentTime, interval: 0, action: action))
     }
 
     public func schedule(after date: VirtualTime, tolerance: VirtualTimeInterval, options: Never?, _ action: @escaping () -> Void) {
-        schedulerQueue.push(TestSchedulerTask(id: nextTaskId(), time: date, action: action))
+        schedulerQueue.push(
+            TestSchedulerTask(id: nextTaskId(), time: date, interval: 0, action: action))
     }
 
     public func schedule(after date: VirtualTime, interval: VirtualTimeInterval, tolerance: VirtualTimeInterval, options: Never?, _ action: @escaping () -> Void) -> Cancellable {
-        let task = TestSchedulerTask(id: nextTaskId(), time: date, action: action)
+        let task = TestSchedulerTask(
+            id: nextTaskId(), time: date, interval: interval, action: action)
         schedulerQueue.push(task)
         return AnyCancellable {
             self.schedulerQueue.remove(task)
@@ -209,11 +234,13 @@ struct TestSchedulerTask {
 
     let id: Int
     let time: VirtualTime
+    let interval: VirtualTimeInterval
     let action: Action
 
-    init(id: Int, time: VirtualTime, action: @escaping Action) {
+    init(id: Int, time: VirtualTime, interval: VirtualTimeInterval, action: @escaping Action) {
         self.id = id
         self.time = time
+        self.interval = interval
         self.action = action
     }
 }

Tests/EntwineTestTests/TestSchedulerTests.swift

@@ -34,14 +34,14 @@ final class TestSchedulerTests: XCTestCase {
 
         // this should order by time, then id
 
-        let t0 = TestSchedulerTask(id: 0, time: 200, action: {})
-        let t1 = TestSchedulerTask(id: 1, time: 200, action: {})
-        let t2 = TestSchedulerTask(id: 2, time: 300, action: {})
-        let t3 = TestSchedulerTask(id: 3, time: 300, action: {})
-        let t4 = TestSchedulerTask(id: 4, time: 400, action: {})
-        let t5 = TestSchedulerTask(id: 5, time: 400, action: {})
-        let t6 = TestSchedulerTask(id: 6, time: 100, action: {})
-        let t7 = TestSchedulerTask(id: 7, time: 100, action: {})
+        let t0 = TestSchedulerTask(id: 0, time: 200, interval: 0, action: {})
+        let t1 = TestSchedulerTask(id: 1, time: 200, interval: 0, action: {})
+        let t2 = TestSchedulerTask(id: 2, time: 300, interval: 0, action: {})
+        let t3 = TestSchedulerTask(id: 3, time: 300, interval: 0, action: {})
+        let t4 = TestSchedulerTask(id: 4, time: 400, interval: 0, action: {})
+        let t5 = TestSchedulerTask(id: 5, time: 400, interval: 0, action: {})
+        let t6 = TestSchedulerTask(id: 6, time: 100, interval: 0, action: {})
+        let t7 = TestSchedulerTask(id: 7, time: 100, interval: 0, action: {})
 
         let unsorted = [t0, t1, t2, t3, t4, t5, t6, t7,]
         let sorted = [t6, t7, t0, t1, t2, t3, t4, t5,]
@@ -208,6 +208,90 @@ final class TestSchedulerTests: XCTestCase {
 
         XCTAssertEqual(expected, results.recordedOutput)
     }
+    
+    func testSchedulesAndCancelsRepeatingTask() {
+        
+        let subject = TestScheduler(initialClock: 0)
+        let publisher1 = PassthroughSubject<VirtualTime, Never>()
+        let results = subject.createTestableSubscriber(VirtualTime.self, Never.self)
+        
+        subject.schedule(after: 100, { publisher1.subscribe(results) })
+        let cancellable = subject.schedule(
+            after: 200,
+            interval: 2,
+            tolerance: subject.minimumTolerance,
+            options: nil,
+            { publisher1.send(subject.now) }
+        )
+        subject.schedule(after: 210, { cancellable.cancel() })
+        subject.resume()
+        
+        let expected: TestSequence<VirtualTime, Never> = [
+            (100, .subscription),
+            (200, .input(200)),
+            (202, .input(202)),
+            (204, .input(204)),
+            (206, .input(206)),
+            (208, .input(208)),
+            (210, .input(210)),
+        ]
+        
+        XCTAssertEqual(expected, results.recordedOutput)
+    }
+    
+    func testIgnoresTasksAfterMaxClock() {
+        let subject = TestScheduler(initialClock: 0, maxClock: 500)
+        let publisher1 = PassthroughSubject<VirtualTime, Never>()
+        let results = subject.createTestableSubscriber(VirtualTime.self, Never.self)
+        
+        subject.schedule(after: 100, { publisher1.subscribe(results) })
+        let cancellable = subject.schedule(
+            after: 0,
+            interval: 100,
+            tolerance: subject.minimumTolerance,
+            options: nil,
+            { publisher1.send(subject.now) }
+        )
+        subject.resume()
+        cancellable.cancel()
+        
+        let expected: TestSequence<VirtualTime, Never> = [
+            (100, .subscription),
+            (100, .input(100)),
+            (200, .input(200)),
+            (300, .input(300)),
+            (400, .input(400)),
+            (500, .input(500)),
+        ]
+        
+        XCTAssertEqual(expected, results.recordedOutput)
+    }
+    
+    func testRemovesTaskCancelledWithinOwnAction() {
+        let subject = TestScheduler(initialClock: 0, maxClock: 500)
+        let publisher1 = PassthroughSubject<VirtualTime, Never>()
+        let results = subject.createTestableSubscriber(VirtualTime.self, Never.self)
+        var cancellables = Set<AnyCancellable>()
+        
+        subject.schedule(after: 100, { publisher1.subscribe(results) })
+        subject.schedule(
+                after: 200,
+                interval: 100,
+                tolerance: subject.minimumTolerance,
+                options: nil) {
+                    publisher1.send(subject.now)
+                    cancellables.removeAll()
+                }
+            .store(in: &cancellables)
+        subject.resume()
+        
+        let expected: TestSequence<VirtualTime, Never> = [
+            (100, .subscription),
+            (200, .input(200))
+        ]
+        
+        XCTAssertEqual(expected, results.recordedOutput)
+    }
 
     static var allTests = [
         ("testSchedulerTasksSortSensibly", testSchedulerTasksSortSensibly),
@@ -216,5 +300,11 @@ final class TestSchedulerTests: XCTestCase {
         ("testSchedulerInvokesDeferredTask", testSchedulerInvokesDeferredTask),
         ("testSchedulerInvokesDeferredTaskScheduledForPastImmediately", testSchedulerInvokesDeferredTaskScheduledForPastImmediately),
         ("testSchedulerRemovesCancelledTasks", testSchedulerRemovesCancelledTasks),
+        ("testSchedulerQueues", testSchedulerQueues),
+        ("testFiresEventsScheduledBeforeStartCalled", testFiresEventsScheduledBeforeStartCalled),
+        ("testTrampolinesImmediatelyScheduledTasks", testTrampolinesImmediatelyScheduledTasks),
+        ("testSchedulesRepeatingTask", testSchedulesAndCancelsRepeatingTask),
+        ("testIgnoresTasksAfterMaxClock", testIgnoresTasksAfterMaxClock),
+        ("testRemovesTaskCancelledWithinOwnAction", testRemovesTaskCancelledWithinOwnAction)
     ]
 }