REGRESSION TESTING Audrius Čėsna IFM-0/2

Regression testing is any type of software testing that seeks to uncover new errors, or regressions, in existing functionality after changes have been made to the software, such as functional enhancements, patches or configuration changes. From the start of the software project, every new capability is accompanied by a short test battery. This battery tests the new capability as thoroughly as the designers want. It is easy to create because the only concern is the new capability, and that capability is fresh- coded, or better, yet to be coded What is regression testing?

Anytime new capability is added, with its new test battery, all previous, validated tests are run, and the results are compared with the standard results already stored on file. This is what is called a regression test. Computer time is the cheapest resource around. Anything that goes wrong with the old tests can be traced to something done between the last time the regression test was run, and the time the latest one has run. Normally, that would be twenty-four hours. The same full regression test is run whenever the implementation is changed, even if no new capability is introduced When execute?

You can quickly write small applications simply to test a portion of your project, for example, to test one specific dialog (perhaps using internal variables as "output") or to run through a specific sequence of operations. If this is done every day (perhaps in the evening), then the "unintended results" found can be traced out quickly (say, at the start of the next day), fixed and re-tested (full regression test, as always). At that point, you know that your application, in its current state, passes every single test you ever thought up for it, and found to be useful

All of these little tests have been written quickly, each to try one aspect or feature of your software’s capability. It is the sum of them that creates the overall regression test in one solid format and lends itself to the concept of regression testing. There is a programming method that takes this one step further - the complete regression test runs several times a day. The method is called Extreme Programming

Record actions as default Windows input commands (toggling a check box, modifying an edit box, etc.), not as absolute, blind, screen-relative actions. In fact, not only should the default recording be relative to controls, but it should locate them by the window they belong to, and identify this window by its window class, instance number and, optionally, by its caption, and this should be done all automatically Testing Software and Regression Testing

Test input goes double for test output. The automated test should allow output to be read off the screen in Windows terms (as well as in pixel terms for special cases). It should also be able to get and read output files. Automated output analysis. The automated test must support comparisons, take decisions and signal its results to the automated testing software Testing Software and Regression Testing