The Atacama Large Millimeter Array (ALMA) is a joint project between astronomical organizations in Europe, North
America, and Japan. ALMA will consist of at least 50 twelve meter antennas operating in the millimeter and submillimeter
wavelength range. It will be located at an altitude above 5000m in the Chilean Atacama desert. The ALMA
Test Facility (ATF), located in New Mexico, USA, is a proving ground for development and testing of hardware,
software, commissioning and operational procedure.
At the ATF emphasis has shifted from hardware testing to software and operational functionality. The support of the
varied goals of the ATF requires stable control software and at the same time flexibility for integrating newly developed
features. For this purpose regression testing has been introduced in the form of a semi-automated procedure. This
supplements the established offline testing and focuses on operational functionality as well as verifying that previously
fixed faults did not re-emerge.
The regression tests are carried out on a weekly basis as a compromise between the developers' response- and the
available technical time. The frequent feedback allows the validation of submitted fixes and the prompt detection of sideeffects
and reappearing issues. Results of nine months are presented that show the evolution of test outcomes, supporting
the conclusion that the regression testing helped to improve the speed of convergence towards stable releases at the ATF.
They also provided an opportunity to validate newly developed or re-factored software at an early stage at the test
facility, supporting its eventual integration. Hopefully this regression test procedure will be adapted to commissioning
operations in Chile.