1. A system for testing a software application supporting reuse of test assets, the system comprising: a testing repository database, the testing repository database storing reusable action object data, test step object data, predetermined categories of test data, reusable test scenario data, and test driver information; a user interface permitting a user to construct a test plan by assembling together at least one of a plurality of reusable action objects and a plurality of reusable scenario objects in a sequence to create a plurality of reusable executable step objects collectively forming a test executable, the reusable executable step objects having associated predetermined categories of test data; and means for late binding instances of actual test data to the predetermined categories of test data following completion of test planning and immediately prior to test execution.