Top Black Box Test Case Design Techniques

Key Takeaways:

1. Black Box Testing is a common practice in daily life, regardless of formal training, where individuals interact with systems without knowing their internal workings.
2. Popular test case design techniques include methods for effectively conducting Black Box Testing.
3. Test case design techniques involve treating the system under test as a mystery box, emphasizing interaction without prior knowledge of its internal mechanisms.

This mystery box means that you are not adequately informed about the system’s internal workings, but you know how it should operate. Black Box Testing is also referred to as testing for actions, opaque-box, closed-box, specification-based or eye-to-eye. 

It is a form of software testing that analyses software/functionality application’s without knowing anything about the internal structure/design of the object being evaluated and compares the value of the input with the value of the output.

What is Black Box Testing 

In Black Box Research the primary emphasis is on the system’s functionality as a whole. For Black Box Testing, the term ‘Behavioral Testing’ is often used in test cases. The design of the behavioural test is somewhat different from the design of the black-box test since the use of internal information is not explicitly prohibited, but it is also prohibited. 

Each method of test case design technique has its perks and drawbacks. Several bugs cannot be identified by using the only black box or only white box method. The majority of apps are checked using the Black Box methodology. 

The majority of test cases need to be protected so that none of the vulnerabilities is found by a Black-Box approach. This research takes place during the life cycle of software development and testing, i.e. in Unit, Integration, System, Acceptance, and Regression Testing phases.

Styles of Black Box Testing 

There are practically many forms of Black Box Testing that are feasible, but if we consider the main version of the test case then the two main ones are described below.

1. Functional Testing

This form deals with an application’s functional requirements or specifications. Hereby offering the input and comparing the actual output with the predicted output, various behaviour or functions of the device are evaluated. For instance, when a drop-down list is checked, we click on it and check that it expands and that all the expected values are shown in the list.

A few major types of Functional Testing are:

• Smoke Testing
• Sanity Testing
• Integration Testing
• System Testing
• Regression Testing
• User Acceptance Testing

2. Non-Functional Review

There are also many non-functional test case design techniques, apart from the functionality of the specifications that need to be tested to enhance the consistency and efficiency of the application.

Non-Functional Testing Types include:

• Usability Testing
• Load Testing
• Performance Testing
• Compatibility Testing
• Stress Testing
• Scalability Testing

Tools for Black Box Testing  

The testing tools for the Black Box are primarily recording and replay tools. For Regression Testing, these tools are used to verify if a new build has created a flaw in the previous features of the working application. In the form of some scripts like TSL, VB script, JavaScript, Perl, etc., these record and playback tools record test cases.

Difference Between Test Plan and Test Strategy

The basic difference between test plan and test strategy is – A software project test plan can be defined as a document that describes the scope, aim, method and focus on a software testing effort whereas the test strategy is a set of instructions that clarify the nature of the test and decide how to conduct the tests.

Black Box Test Case Design Techniques 

There is a need to construct test cases to consistently test a set of functions. Using the following Black Box Testing techniques, researchers may build test cases from the requirement specification text.

1. Partitioning Equivalence

Often known as equivalence class partitioning, this approach is (ECP). In this approach, input values are divided into different classes or categories based on their similarity to the result of the system or application. Therefore, instead of using every input value, we can now use any one group/class value to evaluate the result. In this way, while we can minimize a lot of rework and most significantly, the time spent, we can preserve the test coverage.

2. Decision Table Testing

As the name itself implies, wherever logical relationships occur, such as:

If

{

(Condition = True)

then action1 ;

}

else action2; /*(condition = False)*/

For two conditions, a tester will then consider two outputs (action1 and action2) (True and false). So a decision table is carved to plan a series of test cases based on the probable scenarios.

3. Testing for Phase Transition

State Transfer Testing is a method used for testing the various states of the system being studied. Depending on the circumstances or incidents, the state of the system varies. The events trigger states that become situations and need to be checked by a tester. 

A formal diagram of state transition provides a clear view of changes in the state but is useful for simpler applications. More complex projects can lead to more complex diagrams of transitions, making them less effective.

4. Error Guessing

Experience-Based Testing is a perfect example. The technician will use his/her knowledge with application actions and features in this methodology to estimate the areas that are vulnerable to error. Using error guessing, several defects can be found where most developers normally create errors. Some basic mistakes that developers typically fail to deal with

• Divide by zero.
• Handling null values in fields of text.
• Accepting, without any value, the Submit button.
• Uploading file without connection.
• Upload a file with less than or greater than the size limit.

5. Methods for Graph-Based Testing

Every app is a build-up of certain items. It defines all such objects and prepares the graph. Each object relationship is defined from this object graph and test cases are written appropriately to explore the errors.

6. Checking of Similarities

Different separate versions of the same program are used in this approach to compare each other for testing.

What are The Pros and Cons of Black Box Testing and Test Case Design Techniques

Various pros are given below:

• The tester doesn’t need to have a professional background. Testing by being in the shoes of the user and thinking from the point of view of the user is important.
• If the project/application development is completed, testing can be initiated. Without intervening with each other’s rooms, both the testers and developers work independently.
• For large and complicated applications, it is more effective.
• At the early stage of testing, flaws and anomalies may be detected.

Various cons are given below:

• There are risks of missing potential conditions of the scenario to be evaluated, without any technical or programming expertise.
• There are possibilities for less testing and ignoring all potential inputs and their output testing at a specified time.
• For large and complex projects, full test coverage is not feasible.

Conclusion

Black Box Testing is therefore a form of software test case design technique in which the features of software applications are evaluated 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 requirements and specifications for software.

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