RUnit - A Unit Test Framework for R

Software development for production systems presents a challenge to the development team as the quality of the coded package(s) has to be constantly monitored and verified. We present a generic approach to software testing for the R language modelled after successful examples such as JUnit, CppUnit, and PerlUnit. The aim of our approach is to facilitate development of reliable software packages and provide a set of tools to analyse and report the software quality status. The presented framework is completely implemented within R and does not rely on external tools or other language systems. The basic principle is that every function or method is accompanied with a test case that queries many calling situations including incorrect invocations. A test case can be executed instantly without reinstalling the whole package a feature that is necessary for parallel development of functionality and test cases. On a second level one or more packages can be tested in a single test run, the result of which is reported in an well structured test protocol. To