You have been asked to automate a set of functional tests at system Test level via the CLI of the SUT for the first release of a software system. The automated tests will be delivered to the learn in change of maintenance testing, who will use them for part of the regression testing. They have the following requirements.

1. The automated tests must be as fast and cheap to maintain as possible

2. The cost of adding new automated tests must be as low as possible

3. The automated tests musthave a high level of independence from the tool itself

Which of the following scripting techniques would be MOST suitable?