State-Model-Based Testing

[thiruvasagamani]

Test Styles/Types and Test Qualities

State-Model-Based Testing

In state-model-based testing, you model the visible behavior of the program as a state machine and drive the program through the state transitions, checking for conformance to predictions from the model. This approach to testing is discussed extensively at www.model-basedtesting. org.

In general, comparisons of software behavior to the model are done using automated tests and so the failures that are found are found easily (easy to evaluate).

In general, state-model-based tests are credible, motivating and easy to troubleshoot. However, state-based testing often involves simplifications, looking at transitions between operational modes rather than states, because there are too many states (El-Far 1995). Some abstractions to operational modes are obvious and credible, but others can seem overbroad or otherwise odd to some stakeholders, thereby reducing the value of the tests. Additionally, if the model is oversimplified, failures exposed by the model can be difficult to troubleshoot.
Talking about his experiences in creating state models of software, Harry Robinson (2001) reported that much of the bug-finding happens while doing the modeling, well before the automated tests are coded. Elisabeth Hendrickson (2002) trains testers to work with state models as an exploratory testing tool--her models might never result in automated tests, their value is that they guide the analysis by the tester.