test(reminders): cover schedule edge cases

utils/__tests__/schedule.test.ts

@@ -254,6 +254,50 @@ describe('Schedule Utilities', () => {
       const uniqueIds = new Set(ids);
       expect(uniqueIds.size).toBe(ids.length);
     });
+
+    test('should include reminders at end of window when aligned with frequency', () => {
+      const reminder = createMockReminder({
+        startTime: '09:00',
+        endTime: '10:00',
+        frequencyMinutes: 30,
+      });
+
+      const schedule = generateReminderSchedule([reminder], baseDate);
+
+      const times = schedule.map(instance =>
+        instance.scheduledTime.toTimeString().slice(0, 5)
+      );
+      expect(times).toEqual(['09:00', '09:30', '10:00']);
+    });
+
+    test('should not exceed the time window when frequency does not divide evenly', () => {
+      const reminder = createMockReminder({
+        startTime: '09:00',
+        endTime: '09:40',
+        frequencyMinutes: 25,
+      });
+
+      const schedule = generateReminderSchedule([reminder], baseDate);
+
+      const times = schedule.map(instance =>
+        instance.scheduledTime.toTimeString().slice(0, 5)
+      );
+      expect(times).toEqual(['09:00', '09:25']);
+    });
+
+    test('should handle frequency larger than window by returning a single reminder', () => {
+      const reminder = createMockReminder({
+        startTime: '14:00',
+        endTime: '14:10',
+        frequencyMinutes: 30,
+      });
+
+      const schedule = generateReminderSchedule([reminder], baseDate);
+      expect(schedule).toHaveLength(1);
+      expect(schedule[0].scheduledTime.toTimeString().startsWith('14:00')).toBe(
+        true
+      );
+    });
   });
 
   describe('error handling', () => {