diff --git a/test/features/tasks/data/tasks_dao_test.dart b/test/features/tasks/data/tasks_dao_test.dart
index fa13da1..f5729e6 100644
--- a/test/features/tasks/data/tasks_dao_test.dart
+++ b/test/features/tasks/data/tasks_dao_test.dart
@@ -317,6 +317,79 @@ void main() {
       expect(overdueCount, 1);
     });
 
+    test('completeTask on due date preserves rhythm', () async {
+      // Weekly task due 2026-03-24, completed on 2026-03-24: next due = 2026-03-31
+      final id = await db.tasksDao.insertTask(
+        TasksCompanion.insert(
+          roomId: roomId,
+          name: 'Weekly On Due Day',
+          intervalType: IntervalType.weekly,
+          effortLevel: EffortLevel.medium,
+          nextDueDate: DateTime(2026, 3, 24),
+        ),
+      );
+
+      await db.tasksDao.completeTask(id, now: DateTime(2026, 3, 24));
+
+      final tasks = await db.tasksDao.watchTasksInRoom(roomId).first;
+      expect(tasks.first.nextDueDate, DateTime(2026, 3, 31));
+    });
+
+    test('completeTask before due date recalculates from today', () async {
+      // Weekly task due 2026-03-28, completed on 2026-03-24 (Tuesday): next due = 2026-03-31 (7 days from today)
+      final id = await db.tasksDao.insertTask(
+        TasksCompanion.insert(
+          roomId: roomId,
+          name: 'Weekly Before Due Day',
+          intervalType: IntervalType.weekly,
+          effortLevel: EffortLevel.medium,
+          nextDueDate: DateTime(2026, 3, 28),
+        ),
+      );
+
+      await db.tasksDao.completeTask(id, now: DateTime(2026, 3, 24));
+
+      final tasks = await db.tasksDao.watchTasksInRoom(roomId).first;
+      expect(tasks.first.nextDueDate, DateTime(2026, 3, 31));
+    });
+
+    test('completeTask daily task on non-due day recalculates from today', () async {
+      // Daily task due 2026-03-26, completed on 2026-03-24: next due = 2026-03-25 (tomorrow)
+      final id = await db.tasksDao.insertTask(
+        TasksCompanion.insert(
+          roomId: roomId,
+          name: 'Daily Non-Due Day',
+          intervalType: IntervalType.daily,
+          effortLevel: EffortLevel.low,
+          nextDueDate: DateTime(2026, 3, 26),
+        ),
+      );
+
+      await db.tasksDao.completeTask(id, now: DateTime(2026, 3, 24));
+
+      final tasks = await db.tasksDao.watchTasksInRoom(roomId).first;
+      expect(tasks.first.nextDueDate, DateTime(2026, 3, 25));
+    });
+
+    test('completeTask monthly task early preserves anchor', () async {
+      // Monthly task due 2026-03-28 anchorDay=28, completed on 2026-03-24: next due = 2026-04-28
+      final id = await db.tasksDao.insertTask(
+        TasksCompanion.insert(
+          roomId: roomId,
+          name: 'Monthly Early Completion',
+          intervalType: IntervalType.monthly,
+          effortLevel: EffortLevel.high,
+          nextDueDate: DateTime(2026, 3, 28),
+          anchorDay: const Value(28),
+        ),
+      );
+
+      await db.tasksDao.completeTask(id, now: DateTime(2026, 3, 24));
+
+      final tasks = await db.tasksDao.watchTasksInRoom(roomId).first;
+      expect(tasks.first.nextDueDate, DateTime(2026, 4, 28));
+    });
+
     test('hard deleteTask still removes task and its completions', () async {
       final id = await db.tasksDao.insertTask(
         TasksCompanion.insert(