introduction to testing development timeit forms major part of quality assurance (qaand user acceptance testing it should be noted that with the advent of test-driven developmentthe emphasis on testing against requirements during development has become significantly higher there are of course many other aspects to testingfor exampleperformance testing which identifies how system will perform as various factors that affect that system change for exampleas the number of concurrent requests increaseas the number of processors used by the underlying hardware changesas the size of the database grows etc however you view testingthe more testing applied to system the higher the level of confidence that the system will work as required what should be testedan interesting question is 'what aspects of your software system should be subject to testing?in generalanything that is repeatable should be subject to formal (and ideally automatedtesting this includes (but is not limited to)the build process for all technologies involved the deployment process to all platforms under consideration the installation process for all runtime environments the upgrade process for all supported versions (if appropriatethe performance of the system/servers as loads increase the stability for systems that must run for any period of time ( systemsthe backup processes the security of the system the recovery ability of the system on failure the functionality of the system the integrity of the system notice that only the last two of the above list might be what is commonly considered areas that would be subject to testing howeverto ensure the quality of the system under considerationall of the above are relevant in facttesting should cover all aspects of the software development lifecycle and not just the qa phase during requirements gathering testing is the process of looking for missing or ambiguous requirements during this phase consideration should also be made with regard to how the overall requirements will be testedin the final software system