Wiki is one of the most successful technologies in Web 2.0 because it is so simple that anyone can start using it instantly. The main aim of this research is to realize a collaborative programming environment that is as simple as Wiki. Each Wiki page contains source code of a Scheme function which is executed on the server. Users can edit any function at any time without complicated procedure, and see the results of their changes instantly. In order to avoid intentional or unintentional destruction of working programs, when users attempt to modify existing functions, the modified version must pass unit tests written by other users. Though changes are made anonymously, we can have some confidence if test cases are written by many users.