A test structure for testing graphical user interface applications (GAPs) modularizes test scripts by separating statements that define GAP test logic from statements that navigate to GAP objects. Composition rules weave the statements together to generate the test scripts that are executed to test the GAP. Because the test structure is modular, test logic can be reused across different GAPs and different versions of the same GAP. Reusing test logic is not only an efficient practice from a test engineer's point of view, but also leads to a reduction in test programming errors. The modular test structure also facilitates the efficient modification of test scripts to account for modifications in the underlying GAPs, greatly reducing the time, cost, and resource expenditures needed to arrive at updated test scripts.