A test harness development component streamlines the design of regression test harnesses for testing text-based software. An auto-recording tool to automatically record the input and output data in an actual run of the testing session and to automatically generate a test harness. The test harness development component provides an auto-executing tool to automatically run the test harness in subsequent regression tests. The test harness language is used to specify the tests, validation rules of the results, and any other rules for running the test of a test harness. The test harness language is human-readable and emulates the manual test procedures with very little overhead.