Fastest is a model-based testing tool that works with specifications written in the Z notation. The tool implements (Cristia & Rodriguez Monetti 2009) the Test Template Framework (TTF) proposed by Phil Stocks and David Carrington in (Stocks & Carrington 1996). It is freely available online.
Contents
Usage
Fastest presents a command-line user interface. The user first needs to load a Z specification written in LaTeX format verifying the ISO standard (Z Standard 2002). Then, the user has to enter a list of the operations to test as well as the testing tactics to apply to each of them. In a third step Fastest generates the testing tree of each operation. After testing trees have been generated, users can browse them and their test classes, and, more importantly, they can prune any test class both automatically or manually. Once testing trees have been pruned, users can instruct Fastest to find one abstract test case for each leaf in each testing tree. (Cristia, Rodriguez Monetti & Albertengo 2009)
Testing tactics supported by Fastest
Currently, Fastest supports the following testing tactics:
Pruning testing trees in Fastest
Fastest provides two ways of pruning testing trees (Cristia, Rodriguez Monetti & Albertengo 2010):
How Fastest finds abstract test cases
The tool finds abstract test cases by calculating a finite model for each leaf in a testing tree (Cristia & Rodriguez Monetti 2009). Finite models are calculated by restricting the type of each VIS variable to a finite set and then by calculating the Cartesian product between these sets. Each leaf predicate is evaluated on each element of this Cartesian product until one satisfies the predicate (meaning that an abstract test case was found) or until it is exhausted (meaning that either the test class is unsatisfiable or the finite model is inadequate). In the last case, the user has the chance to assist the tool in finding the right finite model or to prune the test class because it is unsatisfiable.
Architecture and Technology
Fastest is a Java application based on the Community Z Tools (CZT) project. The tool can be used in one of two modes (Cristia & Rodriguez Monetti 2009):
Adding new testing tactics
As can be seen from the TTF presentation, testing tactics are essential to the method. They are the tools that engineers must use to create the most discovering test cases possible. Then, the more sound testing tactics available to engineers the better.
In Fastest users can add testing tactics of their own by implementing the Tactic interface provided by the tool. This interface has methods to configure and apply testing tactics. The interface definition is the following: