Incremental program testing in a very high level language

Abstract

A testing and debugging methodology is presented which exploits the following properties of very high level languages: functionality, single assignment property, locality of reference, and aggregate operations. The approach is based on incremental construction of a program with testing and debugging in parallel using a graphic display and light pen. It is shown how these properties allow execution of arbitrarily small phrases of the program to obtain aggregate values. The emphasis on data flow rather than control flow permits causal errors to be traced by bottom-up or top-down scans of the program tree. Examples of the methodology are given using the Business Definition Language.