Blackbox Testing

Blackbox testing is a software testing method in which the internal implementation of the functions is not known by the tester. Black box testing is like testing a light switch button, as the tester you don’t know what wires are inside, all you do is test if the switch is working as it should.

Imagine testing a new website without the knowledge of the internal structure of the website; you test the website by using a browser where you provide inputs, click keystrokes and verify the output against the expected outcome method is called black box testing because the software program in the eye of the tester is like a black box, where the inside is not visible.

Some of the reasons for black box testing is to attempt to find errors in the following;

  • Behavioral issues

  • Interface errors

  • Errors in data structure

  • Incorrect or missing functions

Types of Blackbox Testing

There are three(3) types of black box testing, namely;

  1. Functional Testing: This testing is done by the software testers to know how the system performs, functional testing is part of system testing and it is based on the client's requirement. Functional testing looks at what software is supposed to do and makes sure it's working how it ought to. Mobile testing is functional and usability testing is non-functional

  2. Non-functional Testing: This type of software testing checks the non-functionality aspects of the software applications, such as; performance testing, usability testing, and reliability testing. Non-functionality is based on the client's expectation and it is done to validate the performance of an application. It is also part of system testing.

  3. Regression Testing: Whenever there's a change or modification in software by developers even if it is a small change, regression testing is done. Regression testing is testing the existing applications to make sure changes or addition that was done by the developer has not broken any existing functionality and to ensure that the application is working as it ought to.

While software testers perform black box testing, there are several techniques that make a tester's life easy and help to catch major bugs.

Black box techniques

  • Equivalence partitioning: This technique is used to minimize the number of possible test cases to an optimum level while maintaining a reasonable test coverage. It is a black box technique in which test cases are designed to exercise one representative of each partition.

  • Boundary value analysis: Boundary value analysis testing techniques are used to identify errors at boundaries. Boundaries like -1 to 100, it is the most suitable for a system where inputs are within certain ranges.

  • Decision table: A decision table is a visual representation of which activities to perform depending on given conditions. It is a good way to record complex business rules that the system must implement.

  • State transition: This technique is used when features of a system are represented as "state" which transforms into one another. The state transition table shows all valid transitions and potential invalid transitions between states, as well as the events, guard conditions, and resulting actions for valid transitions.

  • Use case testing: Use case testing is user oriented and explains real-life user scenarios and it is much easier to understand all the team members. Each use case specifies some behaviour that a subject can perform in collaboration with one or more actors. use case testing is a black box testing technique which helps software testers to write better test cases to increase the quality of the software.

    White box testing

    Unlike black box testing which has to do with testing the functionality of the software without knowing the internal structures of the application, White box testing is a method of testing the software that tests the internal structure of an application as opposed to its functionality.

    Whitebox testing is a software testing technique in which the tester has full access to the internal structure, code, and logic of the software being tested. It is also known as structural testing or code-based testing.

The main objective of white box testing is to ensure that the software functions as intended and meets the specified requirements. It involves testing the internal components of the software, such as the algorithms, data structures, and code paths.

Whitebox testing is typically performed by developers or specialized software testers who have a deep understanding of the software's architecture, design, and implementation. It is often used in conjunction with black box testing, which is a testing technique that focuses on the external behavior of the software without examining its internal workings.

In conclusion, both blackbox and whitebox testing play important roles in ensuring the quality and functionality of software applications. Blackbox testing allows for an objective evaluation of the software's external behavior and user experience, while whitebox testing provides a more detailed examination of the internal workings of the software.

While both testing techniques have their advantages and limitations, they are often used in combination to achieve comprehensive test coverage. By using a combination of black box and whitebox testing, software development teams can identify defects and issues early in the development process, leading to the faster and more efficient delivery of high-quality software.

Ultimately, the choice of testing technique depends on the specific needs and requirements of the software being developed. By understanding the strengths and weaknesses of each approach, software testers and developers can make informed decisions about which techniques to use and when.