Tcases Plugin

The Tcases Plugin runs Tcases, a model-based test case generator. With Tcases, you define a model of the input space for your system-under-test and a model of the coverage that you want. Then Tcases generates a minimal set of test cases that meets your requirements. For REST-ful API developers, the plugin can also automatically generate the API input space and test cases directly from an OpenAPI v3 definition.

What is the "input space" of the system? The simplest way to look at it is this: the set of all (combinations of) input values that could possibly be applied. Easy to say, but hard to do! For all but the simplest systems, such a set is enormous, perhaps even infinite. You could never afford to build and run all those test cases. Instead, you have to select test cases from a small sample of the input space. But how? If your sample is too big, you'll run out of time before you finish. But if your sample is too small --- or, worse, if it's the wrong subset --- you'll miss lots of defects.

That is the test design problem: given a limited amount of testing effort, how can you minimize the risk of defects? Tcases offers a solution. Tcases gives you a way to define the input space for your system in a form that is concise but comprehensive. Then Tcases allows you to control the number of test cases in your sample subset by specifying the level of coverage you want. You can start with a basic level of coverage, and Tcases will generate a small set of test cases that touches every significant element of the input space. Then you can improve your tests by selectively adding coverage in specific high-risk areas. For example, you can specify pairwise coverage or higher-order combinations of selected input variables.