Comparison to Automated Testing

Test automation is the technique of testing software using software rather than people. A test program is written that exercises the software and identifies its defects. These test programs may be written from scratch, or they may be written utilizing a generic Test automation framework that can be purchased from a third party vendor. Test automation can be used to automate the sometimes menial and time consuming task of following the steps of a use case and reporting the results.

Test automation may be able to reduce or eliminate the cost of actual testing. A computer can follow a rote sequence of steps more quickly than a person, and it can run the tests overnight to present the results in the morning. However, the labor that is saved in actual testing must be spent instead authoring the test program. Depending on the type of application to be tested, and the automation tools that are chosen, this may require more labor than a manual approach. In addition, some testing tools present a very large amount of data, potentially creating a time consuming task of interpreting the results. From a cost-benefit perspective, test automation becomes more cost effective when the same tests can be reused many times over, such as for regression testing and test-driven development, and when the results can be interpreted quickly. If future reuse of the test software is unlikely, then a manual approach is preferred.

From the perspective of practicality, software that does not have a graphical user interface tends to be tested by automatic methods. Things such as device drivers and software libraries must be tested using test programs. In addition, testing of large numbers of users (performance testing and load testing) is typically simulated in software rather than performed in practice.

Conversely, graphical user interfaces whose layout changes frequently are very difficult to test automatically. There are test frameworks that can be used for regression testing of user interfaces. They rely on recording of sequences of keystrokes and mouse gestures, then playing them back and observing that the user interface responds in the same way every time. Unfortunately, these recordings may not work properly when a button is moved or relabeled in a subsequent release. An automatic regression test may also be fooled if the program output varies significantly (e.g. the display includes the current system time). In cases such as these, manual testing may be more effective.

Test automation is the use of software to control the execution of tests, the comparison of actual outcomes to predicted outcomes, the setting up of test preconditions, and other test control and test reporting functions. Commonly, test automation involves automating a manual process already in place that uses a formalized testing process.