voilog-tca-development

name	voilog-tca-development
description	Guide TCA (The Composable Architecture) development for VoiLog iOS app including @ObservableState, @ViewAction, delegate patterns, and TestStore testing. Use when implementing new features, modifying TCA reducers, writing tests, or asking about VoiLog architecture patterns.
metadata	{"author":"VoiLog Team","version":"1.1.0","category":"development","tags":["tca","swiftui","ios","voilog","testing"],"updated":"2026-02-01T00:00:00.000Z"}

VoiLog TCA Development

RULE: テストは必ず書く 新機能・バグ修正・リファクタリングのいずれでも、実装と同時に TestStore テストを作成すること。テストなしの実装は完了とみなさない。

Quick Start

VoiLog uses modern TCA patterns with @ObservableState and @ViewAction.

Feature Template Location

Start with: /ios/VoiLog/Template/FeatureTemplate.swift

Modern Architecture Files

Primary locations (PREFERRED for modifications):

• Recording: /ios/VoiLog/Recording/RecordingFeature.swift
• Playback: /ios/VoiLog/Playback/PlaybackFeature.swift
• App Coordinator: /ios/VoiLog/DebugMode/VoiceAppFeature.swift (VoiceAppFeature)

Legacy location (AVOID modifications):

• /ios/VoiLog/Voice/ - Legacy production code

Instructions

Step 1: Choose the Right Architecture

For new features or modifications:

1. Use Modern Architecture (/ios/VoiLog/Recording, /Playback, /DebugMode)
2. Follow the tab-based pattern with VoiceAppFeature
3. Implement delegate pattern for inter-feature communication

Never modify:

• Files in /ios/VoiLog/Voice/ directory (Legacy)

Step 2: Create New Feature

@Reducer
struct MyFeature {
  @ObservableState
  struct State: Equatable {
    var isLoading = false
    // Add your state properties
  }

  enum Action: ViewAction {
    case view(View)
    case delegate(Delegate)

    enum View {
      case onAppear
      case buttonTapped
    }

    enum Delegate {
      case completed(Result)
    }
  }

  var body: some ReducerOf<Self> {
    Reduce { state, action in
      switch action {
      case .view(.onAppear):
        // Implementation
        return .none

      case .view(.buttonTapped):
        // Send delegate action to parent
        return .send(.delegate(.completed(.success)))

      case .delegate:
        return .none
      }
    }
  }
}

Step 3: Integrate with VoiceAppFeature

For features that need tab switching:

// In VoiceAppFeature
case .recording(.delegate(.recordingCompleted)):
  state.selectedTab = 1 // Switch to playback tab
  return .send(.playback(.reloadData))

Step 4: Write Tests

See "Testing Patterns" section below for comprehensive test examples.

Testing Patterns

Basic TestStore Structure

import ComposableArchitecture
import Testing

@Test
func testBasicAction() async {
  let store = TestStore(initialState: MyFeature.State()) {
    MyFeature()
  }

  // Send action and verify state changes
  await store.send(.view(.buttonTapped)) {
    $0.isLoading = true
  }

  // Verify delegate action received
  await store.receive(.delegate(.completed))
}

Pattern 1: ViewAction → State Change

@Test
func testStateChange() async {
  let store = TestStore(initialState: RecordingFeature.State()) {
    RecordingFeature()
  }

  await store.send(.view(.recordButtonTapped)) {
    $0.recordingState = .recording
    $0.isRecordButtonEnabled = false
  }
}

Pattern 2: ViewAction → Delegate Notification

@Test
func testDelegateNotification() async {
  let store = TestStore(
    initialState: RecordingFeature.State(recordingState: .recording)
  ) {
    RecordingFeature()
  }

  await store.send(.view(.stopButtonTapped)) {
    $0.recordingState = .stopped
  }

  await store.receive(.delegate(.recordingCompleted))
}

Pattern 3: Testing with Dependencies

@Test
func testWithRepository() async {
  let mockMemo = VoiceMemo(
    id: UUID(),
    title: "Test Memo",
    duration: 60.0
  )

  let store = TestStore(initialState: PlaybackFeature.State()) {
    PlaybackFeature()
  } withDependencies: {
    $0.voiceMemoRepository = .mock(
      fetchAll: { [mockMemo] }
    )
  }

  await store.send(.view(.onAppear))
  await store.receive(.memosLoaded([mockMemo])) {
    $0.memos = [mockMemo]
  }
}

Pattern 4: Async Operations

@Test
func testAsyncOperation() async {
  let store = TestStore(initialState: MyFeature.State()) {
    MyFeature()
  }

  await store.send(.view(.loadData)) {
    $0.isLoading = true
  }

  await store.receive(.dataLoadComplete(result: .success(data))) {
    $0.isLoading = false
    $0.data = data
  }
}

Pattern 5: Timer and Debounce

@Test
func testWithTimer() async {
  let clock = TestClock()

  let store = TestStore(initialState: MyFeature.State()) {
    MyFeature()
  } withDependencies: {
    $0.continuousClock = clock
  }

  await store.send(.view(.startTimer)) {
    $0.isTimerRunning = true
  }

  await clock.advance(by: .seconds(1))
  await store.receive(.timerTicked) {
    $0.elapsedTime = 1
  }
}

Pattern 6: Error Handling

@Test
func testErrorHandling() async {
  let store = TestStore(initialState: MyFeature.State()) {
    MyFeature()
  } withDependencies: {
    $0.voiceMemoRepository = .mock(
      fetchAll: { throw TestError.networkError }
    )
  }

  await store.send(.view(.loadData))
  await store.receive(.loadFailed(TestError.networkError)) {
    $0.errorMessage = "Network error"
  }
}

Test Execution Commands

Run all tests

xcodebuild test \
  -project ios/VoiLog.xcodeproj \
  -scheme VoiLogTests \
  -destination 'platform=iOS Simulator,name=iPhone 15'

Run specific test class

xcodebuild test \
  -project ios/VoiLog.xcodeproj \
  -scheme VoiLogTests \
  -destination 'platform=iOS Simulator,name=iPhone 15' \
  -only-testing:VoiLogTests/PlaylistListFeatureTests

Common Test Mistakes

Mistake 1: Missing State Verification

// ❌ Bad: State changes but not verified
await store.send(.view(.buttonTapped))

// ✅ Good: All state changes verified
await store.send(.view(.buttonTapped)) {
  $0.isLoading = true
  $0.buttonTitle = "Loading..."
}

Mistake 2: Missing Action Reception

// ❌ Bad: Delegate action sent but not verified
await store.send(.view(.complete))

// ✅ Good: All received actions verified
await store.send(.view(.complete))
await store.receive(.delegate(.completed))

Mistake 3: Wrong Order

// ❌ Bad: Wrong reception order
await store.receive(.second)
await store.receive(.first)

// ✅ Good: Correct order
await store.receive(.first)
await store.receive(.second)

Common Patterns

Pattern 1: Repository Integration

@Dependency(\.voiceMemoRepository) var repository

// In reducer
case .view(.saveData):
  return .run { [data = state.data] send in
    try await repository.save(data)
    await send(.delegate(.saved))
  }

Pattern 2: Auto Tab Switching

See /ios/VoiLog/DebugMode/VoiceAppFeature.swift for reference:

• Recording completion → Auto switch to playback tab
• Use selectedTab state
• Send reloadData action to target tab

Troubleshooting

Error: State not updating in View

Cause: Forgot @ObservableState macro Solution: Add @ObservableState to State struct

Error: Action not recognized

Cause: Using old WithViewStore pattern Solution: Use @ViewAction pattern instead

Test Error: "Expected state to change but it did not"

Cause: State mutation block provided but state didn't change Solution: Either remove the mutation block or ensure state actually changes

// ❌ Bad: Expects state change but none occurs
await store.send(.view(.noOp)) {
  $0.value = newValue  // But reducer doesn't change this
}

// ✅ Good: No mutation block if no state change
await store.send(.view(.noOp))

Test Error: "Received unexpected action"

Cause: Reducer sent an action that wasn't verified in test Solution: Add await store.receive() for all emitted actions

// ❌ Bad: Missing receive
await store.send(.view(.load))
// Test fails: Unexpected .loadComplete action

// ✅ Good: Verify all received actions
await store.send(.view(.load))
await store.receive(.loadComplete)

Test Error: "TestStore skipped receiving actions"

Cause: Actions received in wrong order or not at all Solution: Verify actions in the exact order they're emitted

// ❌ Bad: Wrong order
await store.receive(.second)
await store.receive(.first)

// ✅ Good: Correct order
await store.receive(.first)
await store.receive(.second)

Test hangs or times out

Cause: Waiting for an action that never comes Solution:

1. Verify the reducer actually sends the expected action
2. Check if async operations completed
3. Use store.exhaustivity = .off for debugging (not recommended for final tests)

References

For detailed examples:

• Recording Feature: /ios/VoiLog/Recording/RecordingFeature.swift
• Playback Feature: /ios/VoiLog/Playback/PlaybackFeature.swift
• App Coordinator: /ios/VoiLog/DebugMode/VoiceAppFeature.swift
• Official TCA Docs: https://github.com/pointfreeco/swift-composable-architecture