A test harness for maintaining unfamiliar software

A process is described that uses the existing code, in a maintenance/test harness, to guide the unfamiliar maintainer through a maintenance activity efficiently. This process uses the code and test cases that execute correctly on the code to build a database of interlocking module tests before maintenance is begun. The maintenance activity is defined by making the changes or additions to the test cases used to build the database thereby defining the desired modification of the software´s function. This is quite different from the conventional, documentation-oriented approach. A description is also given of an existing test harness which implements many of the features of the proposed maintenance/test harness. This implementation has demonstrated feasibility and has provided the experience to establish the software tools required to support the proposed maintenance approach