Black Box Testing & White Box Testing: Know All About It

To ensure the consistency of the application, software needs to be reviewed. The act of constructing test cases using testing techniques in software testing. These test cases and methods are used by testers to test apps so that software meets stakeholders without defects. Besides, software testing also helps detect unintended mistakes, instances of use, or missing specifications. By using various methodologies and methods, testers also evaluate the same code.

What is Black Box testing?

Black Box Testing is a form of software testing wherein the functionality of software applications is tested without knowing the specification of internal code, specifics of execution, and internal paths. Black Box Research focuses primarily on the input and performance of software applications and is focused solely on standards and needs for software. It is called Behavioral Testing as well.

Any software framework you want to try might be the Black-Box above. The operating system such as Windows, a website such as Google, a database like Oracle, or even your custom program, for example. You can test these applications under Black Box Testing by only concentrating on the inputs and outputs without understanding the implementation of their internal code.

How Black Box testing is performed?

Listed below are the steps involved in performing the black box testing

1. Initially, the system’s parameters and requirements are investigated.
2. To verify that SUT processes them correctly, the tester selects valid inputs (positive test scenario). Some invalid inputs are also chosen (negative test scenarios) to check that they can be identified by the SUT.
3. For all those inputs, the tester defines predicted outputs.
4. The program tester creates test cases with the inputs selected.
5. Cases of the examination are executed.
6. The actual outputs are compared by the software tester with the predicted outputs.
7. Defects are corrected and re-tested if there are any.

Types of Black Box Testing

There are many types of Black Box Testing, but the prominent ones are the following-

1. Functional testing-This type of black-box testing is associated with a system’s functional requirements; it is done by software testers.
2. Non-functional testing-This kind of black-box testing does not refer to specific functional testing, but non-functional requirements such as performance, scalability, accessibility.
3. Regression testing- Regression testing is performed after code fixes, improvements, or other maintenance costs to verify that the existing code has not been affected by the new code.

Methods of performing Black Box Testing

1. Class Testing Equivalence: It is used to reduce the number of probable test cases to an ideal level while maintaining acceptable protection of the test.
2. Boundary Value Assessment: The testing of boundary values focuses on boundary values. This approach decides whether or not the machine supports a certain variety of values. In minimizing the number of test cases, it is very useful. For systems in which an input is within such ranges, it is most appropriate.
3. Decision Table Testing: Causes and their results are placed into a matrix by a decision table. In each column, there is a special combination.

What is White Box Testing?

White box testing is a technique for software testing which involves the analysis of the operating system. This study involves the architecture of the code, components of the code, and each device’s execution. The approach was called ‘white-box testing’ since a white box is a transparent box, easily exposing to the software testers the internal structure of the program. By reviewing the code, the tester is capable of evaluating both true and invalid inputs and outputs. 

First, test cases that compare the real output against predicted output can be constructed by the tester. Finally, unit and integration tests may be built by the tester. This is one of two parts of the software testing approach to Box Testing. Black box testing, its equivalent, requires testing from the viewpoint of an external or end-user type. White box testing, on the other hand, is based on an application’s intricacies and focuses on internal testing.

How White Box Testing is performed?

We have split White box testing into two simple steps to give you a simpler description of white box testing. This is what testers do by using the white box research method to test an application:

1. The first things that software testers can always do are read the application’s source code and understand it. Since white box testing requires testing an application’s inner workings, the tester must be very experienced in the programming languages used in the applications they are testing. The testing person must also be extremely conscious of good coding practices. Protection is also one of the primary goals of software testing. The tester should be able to detect security vulnerabilities and avoid attacks by hackers and inexperienced users who could either consciously or unknowingly insert malicious code into the software.
2. The second fundamental step in white box testing includes testing the source code of the application for proper flow and structure. One way is to verify the source code of the program by writing more code. For each process or set of tasks in the application, the tester will create small tests. This technique requires that the tester must have extensive knowledge of the code and the developer always does it.

Types of White Box Testing

Upon reading the program and writing test cases, the tester can write tests. After that, some common types of white box tests can be employed, including:

1. Unit tests-ensure that a single code unit performs as expected. They do this by comparing inputs and outputs that are true/invalid. It is possible to run unit tests if code changes occur. This enables the tester to check that the desired output is delivered by a simple function unit.
2. Integration tests- Such tests ensure that integration works as anticipated between applications. Besides, integration checks should be conducted if code changes occur; this helps the tester to check the integration of code units.
3. Regression tests- These are a series of tests on a function or set of characteristics. These tests allow testers to test a feature or collection of features to learn if there was an unintended effect of a minor change in one position in the code. Regression tests are developed by reusing the test cases for unit and integration tests.
4. Penetration Tests- Tests that target the code (and network) to reveal an app’s vulnerabilities.

Thus the key difference between the two types of testing is: In Black Box, testing is carried out without the knowledge of the program’s internal structure or implementation, while in White Box, testing is carried out with the knowledge of the program’s internal structure. The Black Box test does not require knowledge of programming, while programming knowledge is required for the White Box test.

Also Read: Black Box Penetration Testing