Regression Test

Quality is usually based on a suite of regression tests.   A regression test is written and the results are generated. If the results are in error, then the offending bug is corrected. Finally, the regression test generates verified results. These verified results are called the gold standard.   The terminology "gold standard" was borrowed from financial markets where paper money issued by governments was backed by gold.

Ideally, the validity of a test result would be driven by the requirement document but in practice the implementation team makes this interpretation.

The tests are collected, as well as their gold-standard results, into a regression test suite. As development continues, more tests are added, while old test must still remain valid. The test suite is run generating new results. These new results are then compared with the gold-standard results. If they differ, then a potential new fault has entered the system. The fault is corrected and the development continues. This mechanism detects when new development invalidates existing development and thus prevents the system from regressing into a fault state.

There are four major focuses of regression testing used to assure quality.

A summary can be found in Table  on page  .

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Table: Categories of Quality