Although spreadsheets have been around for over thirty years, we are only just realising their importance. Most companies use spreadsheets in their decision-making processes, but rarely employ any form of testing. This paper shows how an “all-uses” test adequacy technique can be integrated into Microsoft’s Excel. The modular technique adopted makes the implementation spreadsheet package independent. It also includes a user interface, to assist developers specify test cases and a technique for recording test cases and session information. In particular it presents a systematic technique for constructing test cases. As a key problem with spreadsheet development is the inexperience of developers, this paper describes an easy to use tool that will improve the standard of spreadsheets developed.