For testing business logic in my back end applications I mostly used ColumnFixture, TableFixture and RowFixture for defining inputs and output data sets. All I needed to write was a thin adapter or mapper Java class that extends any of these fixtures. That thin adapter Java class just gets input data from wiki and use that data to make a call to my back end application. At the end of the call it just makes the result available for FitNesse to display on wiki page. This thin adapter class is fully Fixture aware and developer of this class must know how to map data between back end application and FitNesse front end wiki page.
So far so good no major complains here, it worked great for us.
But I found this requirement to write the thin fixture adapter class for each new transaction a little annoying and have always toyed with the idea of building a generic Table/Fixture, one that will not require a developer to understand and be aware of the various fixtures coding conventions. In other words a fixture/table style where testers can write acceptance tests without needing development support of writing fixture specific code for each new transaction.
That became the main driving force behind the thought of developing a Generic Fixture where you just drop your class in FitNesse’s class path, write your test tables in wiki and be ready to test without having to write a single line of Java code. This idea is simple enough to understand but not so simple to implement because of the complexity of Java classes. Each class is different, it can have various type of constructors and methods (even overloaded ones). Each method can be returning different type of values (or not returning at all if method is void). We have to define some rules of defining class names, constructors, method names and their return types on wiki test tables first.