Black-box and White-box Testing

Published: June 29, 2012 3 min. read
Svitla Team
By Svitla Team
Quality Assurance
Black-box and White-box Testing

When testing software and programs there are many different types of tests used. Two common test procedures are black-box testing and white-box testing. These formats are used and applied at all levels of testing, including unit, integration, system and acceptance tests.

Black-box testing assesses the functional behavior of the program in terms of the external world. This method can be very effective for external research of software by monitoring and controlling input/output information. In software development, it is possible to study the behavior of systems – that is, a system’s reactions to various external influences – and at the same time abstract from their internal structure. With this test, specific knowledge of the application’s code/internal structure, and even general programming knowledge, is not required. The tester is only aware of what the software is supposed to do – not how it does it. In other words, when the tester enters a certain input, he gets a certain output – without being aware of how the output was produced in the first place

White-box testing is the opposite of black box testing. White-box testing allows access to source codes of software. This method can be very effective when it is necessary to localize a known bug and fix it. “White box” is a test of code for the program logic and correctness of its work from the perspective of a compiler language in which it was written. The strategy of testing with White Box – also known as the strategy of testing control logic of the program – allows the tester to check the internal structure of the program. While this testing can be done at all levels, it is most commonly employed in unit testing.

Quality Assurance

 Working with a current client, we used black-box testing for an application across Android, iOS, and Windows mobile systems. A simple and effective number of unit tests were constructed to be sure that the server worked in the manner expected. The server developers then used white box testing to test the server using unit tests for each platform. The combination of black box and white box testing was able to give good results.

This dual use of white-box and black-box testing in tandem with unit testing helps control the time and labor spent testing. A tester can run automatic testing in the Black Box Mode and it will be able to detect that something is wrong. Instead of many hours of manual testing and using very expensive resources like human testers to manually check every function, a regression test is created through white and black box testing and is able to check for errors much more quickly.

Written by
Svitla Team
Black-box and White-box Testing

FAQ

What is the difference between black-box testing and white-box testing?

Black-box testing evaluates the software’s functionality without knowing its internal code or structure; it only considers whether the correct outputs are produced for the given inputs. White-box testing examines the software’s internal workings and source code so that the testers can confirm logic, code paths, and specific implementations. The former is ideal to check overall behavior, while the latter is ideal to check and fix bugs within the code. Both are ideally used together as standard practice to ensure comprehensive software quality.

What are the benefits and limitations of black box testing?

Black box testing helps evaluate the software’s working from an external perspective without involving the internal code; hence, it helps identify potential usability issues and whether the software lives up to the users’ expectations. This, however, assumes that the test coverage is incomplete because the testers do not know all the possible code paths or internal logic, making it somewhat less efficient at zeroing in on where the bugs are located within the code. These being the above-stated limitations, black box testing is viewed as one of the most important methods of software quality evaluation.

What tools are commonly used for white box testing?

White box testing often involves tools that facilitate code analysis and debugging. Generally, debuggers are used to step through code and examine variables, while static analyzers help identify potential issues like code vulnerabilities or inefficiencies without executing the code. Unit testing frameworks are also essential, allowing developers to write and run tests verifying individual code components’ behavior. These tools collectively aid in ensuring the internal correctness and quality of the software.

What tools are best suited for black box testing?

Black-box testing can be automated to detect issues, but it doesn’t specify particular tools. Generally, test management tools organize and execute test cases, while automated testing tools can simulate user interactions and verify outputs against expected results. Performance testing tools are also valuable for assessing the software’s responsiveness and stability under various conditions. These tools help ensure that the software functions correctly from an external perspective without requiring knowledge of the internal code.