Jul 13, 2020 Namiko
Black box, White box, and Grey box testing: Major distinctions
Software need our commands
Software systems are now ingrained in our daily lives, from business apps to consumer products. Unfortunately, even a single experience with faulty software may result in heavy financial losses for businesses, such as reputation damage and customers, and potentially lead to life-threatening incidents if used by medical or mission-critical applications. To mitigate these risks, software quality testing is becoming increasingly necessary across many industries reliant on digital incomes, ensuring quality while reducing potential failure rates when it comes time for launch day operations.
One of the common misconceptions of testing is that people think it only consists of running tests, i.e., executing the software and checking the results in an Excel sheet. On the contrary, software testing is a process that involves complex activities such as checking the test base itself off errors and test execution. The testing activities also stretch to things like test planning, analyzing, designing, implementing tests, reporting, and evaluating the quality of a test object.
Some testing does involve the execution of the component or system being tested; such testing is called dynamic testing. Other testing does not involve executing the component or system being tested; such testing is called static testing. Tests include reviewing work products, such as requirements, user stories, and source code. Despite another common misconception about testing that focuses entirely on verification, it performs both verification and validation. For example, verification of requirements, user stories, or other specifications and validation checking whether the system will meet user and other stakeholder needs in its operational environment.
Now that we have a baseline understanding of the testing concepts, this article compares different types of testing — Black, White, and Grey box testing.
Black Box Testing
BLACK BOX TESTING is a testing technique in which the “Application Under Test” functionality is tested without examining the internal code structure, implementation details, or knowledge of the software’s internal paths.
In other words, with black box testing, we solely focus on the inputs and outputs of the software system without bothering about internal knowledge of the software program. So, in the above black box, an object can be any software system you want to test. For Example, an operating system like Windows, a website like Google, a database like Oracle, or even your own custom application.
This technique is useful for unit, integration, system, and acceptance testing.
White Box Testing
WHITE BOX TESTING is a software testing method that tests an application’s internal structures or workings instead of its functionality, like black box testing. It is also known as clear box testing, glass box testing, transparent box testing, and structural testing. In white box testing, an internal perspective of the system and programming skills are tested and used to design test cases.
When developing a new digital product, it is almost mandatory to incorporate white box tests into your regular quality assurance routine. Basically, the tester chooses inputs to exercise paths through the code and determines the expected outputs. Therefore, white box testing can be applied at the software testing process’s unit, integration, and system levels.
Although traditional testers tended to think it was best done at the unit level, it is more frequently used for integration and system testing today. This is because it can test paths within a unit, paths between units during integration, and between subsystems during system-level tests.
In order to avoid having errors appear in syntax or spelling, loop structures, code paths, and implementation of code elements into a program, white-box testing is recommended with the following code coverage criteria:
- Control flow testing
- Data flow testing
- Branch testing
- Statement coverage
- Decision coverage
- Modified condition/decision coverage
- Prime path testing
- Path testing
Grey Box Testing
GREY BOX TESTING is a combination of white-box testing and black-box testing. The aim is to search for defects, if any, due to improper structure or application usage.
As we know, understanding the system’s internal structure is essential in white-box testing, but this knowledge is not so necessary in black-box testing. How about in-grey-box testing? Under grey-box testing, testers should have a partial understanding of the structure of the system relevant to the test and access to the database. Grey-box testing is often used in integrated testing. However, based on algorithms and functions, it can also be used at various test levels.
I want to note that grey box testing has various advantages, especially because of the increasing need for speedy and effective testing to satisfy demanding current-day consumers. Many modern-day web-based applications require effective testing because of high-performance expectations and the numerous data and functions being added daily.
What are the differences?
Black box testing | Grey box testing | White box testing |
---|---|---|
Testers have NO knowledge of the internal code or structure. | Testers have LIMITED knowledge of the internal workings. They might know about system architecture or database design but not the specific code. | Testers have FULL knowledge of the internal code and structure. |
Looks at functionality from the user’s perspective. They test features based on requirements and specifications. | Combines functional testing with some knowledge of internal structures to design more targeted tests. | Tests the internal logic and code paths to ensure they function as intended. |
Techniques: Equivalence Partitioning, Boundary Value Analysis, User Story Testing, etc. | Techniques: A mix of black box and white box techniques. They might use API testing or focus on integration points between different modules. | Techniques: Unit testing, code coverage analysis, path testing, etc. |
Techniques: Equivalence Partitioning, Boundary Value Analysis, User Story Testing, etc. | Techniques: A mix of black box and white box techniques. They might use API testing or focus on integration points between different modules. | Techniques: Unit testing, code coverage analysis, path testing, etc. |
Summary
In many cases, performing both grey box and black box testing for applications is important. If many errors are found, a combination of grey box and black box testing helps identify problems and boost performance.
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