2.7 Automated Regression Testing

Automated regression testing is extremely important for several reasons:

1. It allows portability problems to be pinpointed when the program is moved to a new machine.
2. It provides confidence that changes made to the program have not introduced bugs.
3. It provides ongoing confidence in the integrity of FunnelWeb as a programming tool.
4. It provides a practical confirmation of the semantics of FunnelWeb.

The simplest way to set up automated regression testing is to construct a suite of test cases, each of which consists of a test input file and a "correct answer" output file. To test FunnelWeb, the input files are processed and the resulting output files compared with the correct answer output files.

To automate such a list of tests, some kind of scripting language is required. Unfortunately, at the time of writing FunnelWeb (at least), there was no scripting language that was available on all the platforms to which FunnelWeb had to be ported (Macintosh, IBM-PC, Sun, and OpenVMS). So, after some thought, I decided that the best solution to the problem was to create a command language within FunnelWeb  that could be used as a framework for the automation of the testing of the rest of FunnelWeb.

The resultant scripting language is described in the FunnelWeb Reference Manual.