A mother substrate for an organic light-emitting display apparatus. The mother substrate has a panel area and a peripheral area surrounding the panel area, pixels disposed in a display area of the panel area, pads that are disposed in a non-display area of the panel area and are coupled to the pixels, test wirings disposed in the peripheral area, a local buffer electrically connected to the test wirings, a bridge wiring connecting the local buffer to one of the pads, and a dummy resistance layer having one end in contact with the bridge wiring and another end in contact with one of the test wirings.