The forced-error test (FET) consists of negative test cases that are designed to force a program into error conditions. A list of all error messages thatthe program issues should be generated. The list is used as a baseline for developing test cases. An attempt is made to generate each error message in the list. Obviously, test to validate error-handling schemes cannot be performed until all the handling and error message have been coded. However, FETs should be thought through as early as possible. Sometimes, the error messages are not available. The error cases can still be considered by walking through the program and deciding how the program might fail in a given user interface such as a dialog or in the course of executing a given task or printing a given report. Test cases should be created for each condition to determine what error message is generated.