test: harden business boundary conditions

apps/server/src/schedules/dto/schedule.dto.spec.ts

@@ -60,3 +60,30 @@ it('removes the retired departmentId field from create requests', async () => {
 
   expect(dto).not.toHaveProperty('departmentId');
 });
+
+describe('schedule boundary validation', () => {
+  it.each(['24:00', '09:60', '99:99', '9:00'])('rejects invalid time %s', async (time) => {
+    const dto = createSchedule('');
+    dto.startTime = time;
+    expect((await validate(dto)).some((error) => error.property === 'startTime')).toBe(true);
+  });
+
+  it.each(['2026-02-31', '2026-07-13T00:00:00Z', '2026-7-13'])(
+    'rejects invalid or non-date-only value %s',
+    async (date) => {
+      const dto = createSchedule('');
+      dto.startDate = date;
+      expect((await validate(dto)).some((error) => error.property === 'startDate')).toBe(true);
+    },
+  );
+
+  it('accepts inclusive attendance-window limits and a leap-day date', async () => {
+    const zero = createSchedule('');
+    zero.attendanceAdvanceMinutes = 0;
+    zero.startDate = '2028-02-29';
+    const fullDay = createSchedule('');
+    fullDay.attendanceAdvanceMinutes = 1440;
+    expect(await validate(zero)).toEqual([]);
+    expect(await validate(fullDay)).toEqual([]);
+  });
+});