Section 633 of the German Civil Code says when a commissioned work is free of defects: a repaired car, a renovated bathroom, a written program. Das Werk ist frei von Sachmängeln, wenn es die vereinbarte Beschaffenheit hat. The work is free of defects if it has the agreed quality. Only where nothing was agreed does a second test apply. Then the work must suit the use the contract assumes, or ordinary use. A different work than the one ordered counts the same as a defect.