Application Testing Interface Layer
Principle: The ATI layer's responsibility lies with exposing a DSL (domain specific language) through which the SUT can be functionally driven.
Depending on the complexity of the SUT and the expected features of the framework, it could be advantageous to split this layer into two sublayers:
* [Functional Library Sublayer][FunctionalLibrarySublayerLink]
* [UI Map Sublayer][UIMapSublayerLink]
A well designed ATI layer that logically encapsules the functionality of the SUT really pays of as it is the primary factor in creating an easy to maintain test suite.
When refactoring test scripts and applying the DRY (Don't Repeat Yourself) principle, one should always evaluate whether it might be advantageous to instead expand the ATI layer to implement this functionality.
This will also be the framework layer that needs the most refactoring, since it reflects the functionality of the SUT and the mapping of GUI elements to this functionality.