A lot of existing code needs to be maintained. But because code complexity increases with the maintenance and age of the software, adding features or fixing bugs may not be possible without changing the inner workings. Refactoring is a method facilitating these changes. This paper will show how to use refactoring in conjunction with unit testing to improve the design of existing code.

After a short introduction to unit testing, on the basis of an example, I will explain when, how and where refactoring can successfully be applied. Hindering issues will be considered as well.

The third part of the paper is devoted to a short presentation of some tools on the market today that support refactorings and tools that help with unit testing.

Paper

Presentation

Getting to the source

See http://variant.ch/cvs/GenieLogiciel/refactoring/ for CVS. The example application is the same as in Martin Fowler's book "Refactoring - Improving The Design Of Existing Code".

For refactoring the presented source code yourself, you can download a package with all Java source files.

If you want the full package with all sources (Latex, Java etc.), you can get it as well.

License

Permission is granted to copy, distribute and/or modify these documents under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.