An embodiment of the invention provides an integrated circuit including a core circuit and a memory. The core circuit executes operations of the integrated circuit. The memory stores a subsystem and a repair system. When the repair system runs, the repair system detects whether there is a defect in the memory. When the repair system detects the defect, the repair system repairs the defect, and when the repair system does not detect the defect, a fake defect is injected in the memory to verify whether the repair system runs correctly.