Software Testing - Methods
There are different methods that can be used for software testing. This chapter briefly describes the methods available.
The technique of testing without having any knowledge of the interior workings of the application is called black-box testing. The tester is oblivious to the system architecture and does not have access to the source code. Typically, while performing a black-box test, a tester will interact with the system's user interface by providing inputs and examining outputs without knowing how and where the inputs are worked upon.
The following table lists the advantages and disadvantages of black-box testing.
White-box testing is the detailed investigation of internal logic and structure of the code. White-box testing is also called glass testing or open-box testing. In order to perform white-box testing on an application, a tester needs to know the internal workings of the code.
The tester needs to have a look inside the source code and find out which unit/chunk of the code is behaving inappropriately.
The following table lists the advantages and disadvantages of white-box testing.
Grey-box testing is a technique to test the application with having a limited knowledge of the internal workings of an application. In software testing, the phrase the more you know, the better carries a lot of weight while testing an application.
Mastering the domain of a system always gives the tester an edge over someone with limited domain knowledge. Unlike black-box testing, where the tester only tests the application's user interface; in grey-box testing, the tester has access to design documents and the database. Having this knowledge, a tester can prepare better test data and test scenarios while making a test plan.
A Comparison of Testing Methods
The following table lists the points that differentiate black-box testing, grey-box testing, and white-box testing.
|Black-Box Testing||Grey-Box Testing||White-Box Testing|
|The internal workings of an application need not be known.||The tester has limited knowledge of the internal workings of the application.||Tester has full knowledge of the internal workings of the application.|
|Also known as closed-box testing, data-driven testing, or functional testing.||Also known as translucent testing, as the tester has limited knowledge of the insides of the application.||Also known as clear-box testing, structural testing, or code-based testing.|
|Performed by end-users and also by testers and developers.||Performed by end-users and also by testers and developers.||Normally done by testers and developers.|
|Testing is based on external expectations - Internal behavior of the application is unknown.||Testing is done on the basis of high-level database diagrams and data flow diagrams.||Internal workings are fully known and the tester can design test data accordingly.|
|It is exhaustive and the least time-consuming.||Partly time-consuming and exhaustive.||The most exhaustive and time-consuming type of testing.|
|Not suited for algorithm testing.||Not suited for algorithm testing.||Suited for algorithm testing.|
|This can only be done by trial-and-error method.||Data domains and internal boundaries can be tested, if known.||Data domains and internal boundaries can be better tested.|