From 8b4e8ecbde11e7f9f96b7405c98736b93416d393 Mon Sep 17 00:00:00 2001
From: Alexander Ignatov <yalishanda@abv.bg>
Date: Sat, 27 May 2023 00:54:00 +0300
Subject: [PATCH] Add station domain tests

---
 .../StationDomain/StationReducer.swift        |   8 +-
 .../StationDomainTests.swift                  | 140 ++++++++++++++++++
 2 files changed, 146 insertions(+), 2 deletions(-)

diff --git a/BDZDelays/bdz-delays/Sources/StationDomain/StationReducer.swift b/BDZDelays/bdz-delays/Sources/StationDomain/StationReducer.swift
index f7be62d..46356a6 100644
--- a/BDZDelays/bdz-delays/Sources/StationDomain/StationReducer.swift
+++ b/BDZDelays/bdz-delays/Sources/StationDomain/StationReducer.swift
@@ -67,7 +67,11 @@ public struct StationReducer: ReducerProtocol {
             }
             
         case .tick:
-            // Refresh on every new calendar minute.
+            // Auto-refresh only on every new calendar minute and if not errored.
+            guard state.loadingState != .failed else {
+                return .none
+            }
+            
             let isInTheSameMinute = state.lastUpdateTime
                 .map {
                     let components: Set<Calendar.Component> = [.day, .hour, .minute]
@@ -92,7 +96,7 @@ public struct StationReducer: ReducerProtocol {
                 await .receive(TaskResult {
                     try await stationRepository.fetchTrainsAtStation(station)
                 })
-            }
+            }.cancellable(id: TrainsTaskCancelID.self)
             
         case .receive(.success(let trains)):
             state.lastUpdateTime = now
diff --git a/BDZDelays/bdz-delays/Tests/StationDomainTests/StationDomainTests.swift b/BDZDelays/bdz-delays/Tests/StationDomainTests/StationDomainTests.swift
index 79b8c9e..c76aa0c 100644
--- a/BDZDelays/bdz-delays/Tests/StationDomainTests/StationDomainTests.swift
+++ b/BDZDelays/bdz-delays/Tests/StationDomainTests/StationDomainTests.swift
@@ -131,6 +131,146 @@ final class StationDomainTests: XCTestCase {
             $0.lastUpdateTime = Date(timeIntervalSinceReferenceDate: 1)
         }
     }
+    
+    func test_task_sendsTickEverySecond() async throws {
+        let clock = TestClock()
+        let store = TestStore(
+            initialState: .init(
+                station: .sofia
+            ),
+            reducer: StationReducer()
+        ) {
+            $0.continuousClock = clock
+        }
+        
+        store.exhaustivity = .off
+        
+        let task = await store.send(.task)
+        
+        for _ in 1...10 {
+            await clock.advance(by: .seconds(1))
+            await store.receive(.tick)
+        }
+        
+        await task.cancel()  // done by SwiftUI
+    }
+    
+    func test_tick_refreshesWhenInDifferrentMinute() async throws {
+        let dateInNextMinute = Date(timeIntervalSinceReferenceDate: 61)
+        
+        let store = TestStore(
+            initialState: .init(
+                station: .sofia,
+                lastUpdateTime: Date(timeIntervalSinceReferenceDate: 51)
+            ),
+            reducer: StationReducer()
+        ) {
+            $0.date.now = dateInNextMinute
+            $0.calendar = Calendar(identifier: .gregorian)
+            $0.stationRepository.fetchTrainsAtStation = { _ in [] }
+        }
+        
+        await store.send(.tick)
+        
+        await store.receive(.refresh) {
+            $0.loadingState = .loading
+        }
+        
+        await store.receive(.receive(.success([]))) {
+            $0.trains = []
+            $0.lastUpdateTime = dateInNextMinute
+            $0.loadingState = .loaded
+        }
+    }
+    
+    func test_tick_doesNotRefreshWhenInSameMinute() async throws {
+        let store = TestStore(
+            initialState: .init(
+                station: .sofia,
+                lastUpdateTime: Date(timeIntervalSinceReferenceDate: 51)
+            ),
+            reducer: StationReducer()
+        ) {
+            $0.date.now = Date(timeIntervalSinceReferenceDate: 52)
+            $0.calendar = Calendar(identifier: .gregorian)
+            $0.stationRepository.fetchTrainsAtStation = { _ in [] }
+        }
+        
+        await store.send(.tick)
+    }
+    
+    func test_tick_refreshesWhenNoPreviousUpdateTime() async throws {
+        let dateInNextMinute = Date(timeIntervalSinceReferenceDate: 61)
+        
+        let store = TestStore(
+            initialState: .init(
+                station: .sofia,
+                lastUpdateTime: nil
+            ),
+            reducer: StationReducer()
+        ) {
+            $0.date.now = dateInNextMinute
+            $0.calendar = Calendar(identifier: .gregorian)
+            $0.stationRepository.fetchTrainsAtStation = { _ in [] }
+        }
+        
+        await store.send(.tick)
+        
+        await store.receive(.refresh) {
+            $0.loadingState = .loading
+        }
+        
+        await store.receive(.receive(.success([]))) {
+            $0.trains = []
+            $0.lastUpdateTime = dateInNextMinute
+            $0.loadingState = .loaded
+        }
+    }
+    
+    func test_tick_doesNotRefreshWhenErrored() async throws {
+        let dateInNextMinute = Date(timeIntervalSinceReferenceDate: 61)
+        
+        let store = TestStore(
+            initialState: .init(
+                station: .sofia,
+                loadingState: .failed,
+                lastUpdateTime: Date(timeIntervalSinceReferenceDate: 51)
+            ),
+            reducer: StationReducer()
+        ) {
+            $0.date.now = dateInNextMinute
+            $0.calendar = Calendar(identifier: .gregorian)
+            $0.stationRepository.fetchTrainsAtStation = { _ in [] }
+        }
+        
+        await store.send(.tick)
+    }
+    
+    func test_finalize_cancelsEffects() async throws {
+        let clock = TestClock()
+
+        let store = TestStore(
+            initialState: .init(station: .sofia),
+            reducer: StationReducer()
+        ) {
+            $0.stationRepository = StationRepository(
+                fetchTrainsAtStation: { _ in
+                    for await _ in clock.timer(interval: .seconds(1)) {
+                        return []
+                    }
+                    return []
+                }
+            )
+        }
+
+        await store.send(.refresh) {
+            $0.loadingState = .loading
+        }
+        
+        // do not advance clock so that the task is still in flight
+        
+        await store.send(.finalize)
+    }
 }
 
 // MARK: - Helpers