Regression tests provide verification that modifications and enhancements made to a program do not lead to undesired effects. Regression tests are thus re-runs of successfully completed test cases. If some cases did not yield a positive result and subsequent corrections of the source code have been implemented, to ensure that these modifications have no undesired effects on test cases that were executed successfully, it’s necessary not only to re-run failed test cases but all test cases. Tessy provides a batch feature that enables extensive regression testing to take place without any user intervention.

Regression testing often is necessary for software to be revised in terms of code size, performance, maintenance and reusability, while at the same time guaranteeing that existing functionality remains unchanged.

Test Case Adaptation

A situation could arise where further development of the program has resulted in the function under test being so modified that its test cases are no longer executable (e.g. due the introduction of an additional parameter). Since Tessy has already stored information on existing interfaces, it is able to recognize alterations made to an interface and refers the user to them. Tessy’s internal Interface Data Assign editor (IDA) allows efficient assignment of newly introduced interface elements to the elements of an existing interface. The IDA performs this allocation automatically wherever possible. This feature allows continued use of values from old interface elements in new ones. This is possible thanks to the concept of separating interface information from test data.

Further Use of Test Data

The pre-requisite for ensuring test cases are compatible with the latest version of software is that test data, including data for modified interfaces, is reusable in the most efficient and extensive means possible. The re-use of test data allows re-running tests at any time and re-running tests implies regression testing and regression testing is an essential procedure in assuring software quality.