Fastest presents a command-line user interface. The user first needs to load a Z specification written in LaTeX format verifying the ISO standard. 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.
Testing tactics supported by Fastest
Currently, Fastest supports the following testing tactics:
Disjunctive Normal Form. It is the only testing tactic applied by default and the first one to be applied.
Standard partitions. The user can add, modify and delete standard partitions for any predefined Z mathematical operator by simply editing a text file.
The tool finds abstract test cases by calculating a finite model for each leaf in a testing tree. 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 or until it is exhausted. 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.
In distributed mode Fastest works as a client-server application. The application can be installed in a number of computers each acting as client, a server or both. Users access the application through clients which send test classes to servers which try to find an abstract test case out of them. In this way the heaviest task is distributed across as many computers as possible. Since the calculation of an abstract test case from a test class is completely independent from each other, this architecture speeds up the entire process proportionally with respect to the number of testing servers.
In application mode each instance of Fastest is completely independent of each other. All the tasks are computed in the local computer.
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: package client.blogic.testing.ttree.tactics; import java.util.*; import net.sourceforge.czt.z.ast.Spec; import common.z.TClass; import common.z.OpScheme; /** * Interface that abstracts a testing tactic and * makes possible its application to a test class in order to generate new ones. */ public interface Tactic
