Difference Between Black Box Testing and White Box Testing

Black box testing and white box testing both are the methods of testing the software. But, the main difference between black box and white box is that the black box testing checks the functionality of the software (external view) whereas, the white box testing, tests the internal structure or procedural design (internal view) of the software.

Black box testing and white box testing are complementary to each other. In this context, we will discuss some more differences between black box and white box testing in software engineering. We would also discuss black box testing and white box testing technique in brief.

Contents: Black Box Vs White Box Testing

1. Difference Chart
2. What is Black Box Testing?
3. What is White Box Testing?
4. Key Takeaways
5. Conclusion

Difference Chart

Basis of Differentiation	Black Box Testing	White Box Testing
Basic	Tests the functionality of the software.	Tests all the paths in the procedural design of the software.
Schedule	Scheduled at the later stages of testing.	Scheduled at the early stages of testing.
Testers	Testers can be the independent testers, can also be customers.	Testers should be the developers of the software.
Knowledge	Testers are not required to have the programming knowledge or even the implementation knowledge of the software.	Testers must have the knowledge of programming knowledge and must also be aware of the implementation of the software.
Test Cases	Test cases are designed by considering the functional requirement of the software.	Test cases are designed by considering the procedural design of the software.
Tests	Tests if any function is incorrect or missing, interface, database access, initiation and termination of software.	Tests if any function is incorrect or missing, interface, database access, initiation and termination of software.
Time	It is not a time-consuming process.	It consumes a considerable time.
Alternative Name	Behavioral Testing and Functional Testing.	Glass Box Testing and Structural testing.

What is Black Box Testing?

Black box testing is a technique of deriving the test cases that has all possible input conditions which will exercise all the functions of the software. In short, it checks the functionality of the software and that’s why it is called behavioural testing or functional testing.

The test cases derived in black box testing are designed by considering the functional requirements. So, the black box testing ensures that all the functional requirements specified by the customer are satisfied or not. Black box testing checks if there is any function in the software, which is implemented incorrectly or is any function missing the software. It also tests if there is any interface error in the software.

Black box testing also tests whether there is any problem in accessing the database of the software or if there is any problem in storing the data in the database. It also tests whether there is any problem in initializing the software or if there is any problem in the termination of the software.

Black box testing is scheduled at the later stage of testing, i.e. when GUI of the software is ready. Graph-based testing, equivalence partition, boundary value analysis, orthogonal array testing are the methods of black-box testing.

To perform black-box testing, testers are not required to have programming knowledge. Black box testing only tests the functionality of the software. The testers are also not required to have knowledge of how the components of the software are implemented.

Testers can be other than those in the developer team, or the tester can also be among the customer as they are very much aware of their functional requirement. The testers are the independent software testers.

What is White Box Testing?

White box testing is a technique of deriving test cases that ensures execution of each and every path in the program at least once during the testing of software. It is also termed as glass box testing or structural testing.

White box testing is done on the procedural structure of the software, which includes testing of all logical paths in the program. It also tests whether all the components of the software are working properly. If the white box testing is done with extensive care, it results in a 100% correct program.

Basis path testing is one of the techniques of white box testing. The test cases derived using white box testing technique ensures testing of all independent paths in the program at the minimum one time, all the logical conditions are checked at both sides, i.e. true and false.

It also ensures testing of all the loops in the program at their boundaries and inside their boundaries. It also tests the internal data structures to ensure the validity of the data stored.

The testers performing white box testing must have programming knowledge as this testing includes structural testing of software. Generally, the white box testing is performed by the developers as they are aware of the implementation of all the components of the software.

White box testing can be performed at an early stage of testing, i.e. before the GUI of the software is ready. White box testing is a very time consuming and exhaustive process as it includes the thorough testing of the software and close examination of the procedural design of the software.

Key Takeaways

Conclusion

So, these were all the differences between black box testing and white box testing. Both black box testing and white box testing are complementary to each other. Black box testing is implemented at the external view of the software, and white box testing is implemented at the internal view of the software.