Black Box Testing Vs White Box Testing

What is Black Box testing?

In Black-box testing, a tester doesn't have any information about the internal working of the software system. Black box testing is a high level of testing that focuses on the behaviour of the software. It involves testing from an external or end-user perspective. Black box testing can be applied to virtually every level of software testing: unit, integration, system, and acceptance.

What is White Box testing?

White-box testing is a testing technique which checks the internal functioning of the system. In this method, testing is based on coverage of code statements, branches, paths or conditions. White-Box testing is considered as low-level testing. It is also called a glass box, transparent box, clear box or code base testing. The white-box Testing method assumes that the path of the logic in a unit or program is known.

How Is Black Box testing performed? 

Black box testing is done as follows: 

• The first step to black-box testing is to understand the requirement specifications of the application under test. An accurate and precise SRS document should be there. 
• The next step is to evaluate the set of valid inputs and test scenarios to test the software.  The goal is to save time and get good test coverage.
• Prepare the test cases to cover a maximum range of inputs.
• The test cases are run in the system to generate output, which is validated with the expected outcome to mark pass or fail.
• The failed steps are marked and sent to the development team to fix them.
• Retest the system using various testing techniques to verify its recurring nature or to pass it.

 How is White Box Testing perform?

To give you a simplified explanation of white box testing, we have divided it into two basic steps. This is what testers do when testing an application using the white box testing technique:

STEP 1) UNDERSTAND THE SOURCE CODE

The first thing a tester will often do is learn and understand the source code of the application. Since white box testing involves the testing of the inner workings of an application, the tester must be very knowledgeable in the programming languages used in the applications they are testing. Also, the testing person must be highly aware of secure coding practices. Security is often one of the primary objectives of testing software. The tester should be able to find security issues and prevent attacks from hackers and naive users who might inject malicious code into the application either knowingly or unknowingly.

Step 2) CREATE TEST CASES AND EXECUTE

The second basic step to white box testing involves testing the application's source code for proper flow and structure. One way is by writing more code to test the application's source code. The tester will develop little tests for each process or series of processes in the application. This method requires that the tester must have intimate knowledge of the code and is often done by the developer. Other methods include manual Testing, trial, and error testing and the use of testing tools as we will explain further on in this article.

Advantages / Pros of Black Box Testing

• Unbiased tests because the designer and tester work independently.
• Tester is free from any pressure of knowledge of specific programming languages to test the reliability and functionality of an application/software.
• Facilitates identification of contradictions and vagueness in functional specifications.
• Test is performed from a user’s point-of-view and not of the designer’s.
• Test cases can be designed immediately after the completion of specifications.

Advantages / Pros of White Box Testing

• Code optimization by revealing hidden errors.
• Transparency of the internal coding structure which helps derive.
• The type of input data needed to test an application effectively.
• Covers all possible paths of a code thereby, empowering a software engineering team to conduct thorough application testing.
• Enables programmers to introspect because developers can carefully describe any new implementation.
• Test cases can be easily automated.
• Gives engineering-based rules to stop testing an application.

Differences Between Black Box Testing and White Box Testing

Conclusion

White box and black box testing are necessary for successful software delivery but 100% testing is not possible in either of the cases.

A tester should be able to identify how much testing can be done either in the black box or in the white box testing to certify that an application is working as expected.