feat: 完善听力口语辅助状态记录、练习分块与复习抽查间隔机制

kouyu_english/test/unlock_chain_test.dart

@@ -4,9 +4,7 @@ import 'package:kouyu_english/core/app_state.dart';
 import 'package:kouyu_english/core/models.dart';
 import 'package:kouyu_english/core/courses/course_repository.dart';
 
-/// The A0 → A1 → A2 → B1 unlock chain. Crossing out of A0 into A1 additionally
-/// requires passing the A0 stage assessment; higher levels then chain linearly
-/// (finishing the previous unit unlocks the next), with no extra assessment.
+/// Draft packs are loaded for editing and validation but are not learnable.
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
@@ -72,13 +70,13 @@ void main() {
       reason: 'A1 stays locked until A0 is passed',
     );
 
-    // Passing the A0 stage assessment opens the first A1 unit.
+    // Passing the A0 stage assessment does not bypass editorial approval.
     makeA0Passed(state);
     expect(state.a0Passed, isTrue);
-    expect(state.isLessonUnlocked(firstA1.id), isTrue);
+    expect(state.isLessonUnlocked(firstA1.id), isFalse);
   });
 
-  test('A1 → A2 → B1 chain linearly by finishing the previous unit', () {
+  test('draft packs stay locked even when prerequisites are complete', () {
     final state = AppState();
     makeA0Passed(state);
     for (final lesson in a0SeedLessons) {
@@ -89,34 +87,32 @@ void main() {
     final a2 = byLevel('A2');
     final b1 = byLevel('B1');
 
-    // A1 opened, but only the first unit; the second waits on the first.
-    expect(state.isLessonUnlocked(a1.first.id), isTrue);
+    expect(state.isLessonUnlocked(a1.first.id), isFalse);
     expect(state.isLessonUnlocked(a1[1].id), isFalse);
-
-    // Finishing the first A1 unit unlocks the second — no extra gate.
     state.completedLessonIds.add(a1.first.id);
-    expect(state.isLessonUnlocked(a1[1].id), isTrue);
-
-    // A2 stays locked until the last A1 unit is finished.
+    expect(state.isLessonUnlocked(a1[1].id), isFalse);
     expect(state.isLessonUnlocked(a2.first.id), isFalse);
     for (final lesson in a1) {
       state.completedLessonIds.add(lesson.id);
     }
     expect(
       state.isLessonUnlocked(a2.first.id),
-      isTrue,
-      reason: 'A1 → A2 chains linearly, no separate assessment',
+      isFalse,
+      reason: 'Completing draft prerequisites must not open another draft',
     );
 
-    // B1 likewise unlocks only after the last A2 unit.
     expect(state.isLessonUnlocked(b1.first.id), isFalse);
     for (final lesson in a2) {
       state.completedLessonIds.add(lesson.id);
     }
     expect(
       state.isLessonUnlocked(b1.first.id),
-      isTrue,
-      reason: 'A2 → B1 chains linearly',
+      isFalse,
+      reason: 'B1 remains closed until approved',
     );
+    expect(state.nextIncompleteLessonId, isNull);
+    expect(state.allLessonsComplete, isTrue);
+    state.setPlacementStartLesson(a1.first.id);
+    expect(state.placementStartLessonId, 'a0-01');
   });
 }