A Comprehensive Guide to Black Box Testing

What is Black Box testing?

Black Box Software Testing is a type of software testing in which the functionality of software applications is tested without knowing the internal code structure, implementation details, or internal routes. Black Box testing is also called or black box testing also known as "functional testing." Online QA training will help you learn more about black box testing, which explains the basics of black box testing basics. The input and output of software applications are the primary areas of concentration for black box testing in software engineering, which is wholly and exclusively dependent on software requirements and specifications. In some circles, it is also referred to as Behavioral Testing. This testing approach is suitable for practically all stages of the software testing process, including unit, integration, system, and acceptance testing. Testing that is determined by the specifications is another name for this.

Any software system you want to test could act as the BlackBox in the following example. Examples include an operating system like Linux OS, a website like Bing, a database like Oracle, or even a program you created independently. Using the Black Box Testing methodology, you can put these applications through their paces by concentrating on the program's inputs and outputs rather than its internal code implementation.

Techniques for Performing Black Box Testing:

The testing procedure known as black box testing in software testing is a process in which the tester has specialized knowledge about the workings of the software, and it builds test cases to check the correct functionality of the software.For Blackbox testing, having a prior understanding of the software's programming is not mandatory. The input and output of the individual function are tested for developing every test case. A tester is aware of the specific results that can be obtained from a given input but unaware of the process that leads to those results. There are various techniques used in black box testing, such as decision table technique, boundary value analysis technique, state transition, All-pair testing, cause-effect graph technique, equivalence partitioning technique, error guessing technique, use case technique, and user story technique. Within the scope of this qa tutorial, each of these approaches has been broken down into precise depths. If you’re worried about how to start learning QA software testing, refer to the QA software tester career path guide. 

The following is a list of generic tasks that must be completed before any kind of Black Box Testing may be performed:

1. First, an analysis of the system's prerequisites and specifications is carried out.
2. The tester will select legitimate inputs (a positive test scenario) to verify that the SUT appropriately processes these inputs. Additionally, some faulty inputs (a negative test scenario) are selected so that the SUT may be checked to see if it can recognize them.
3. The tester determines the predicted results for each of those inputs.
4. The test cases for the software are constructed using the chosen inputs.
5. The test cases are put through their paces.
6. A critical part of testing software is contrasting the actual outputs with the anticipated ones.
7. If there are any defects, they are corrected and then retested.

Test Cases:

When developing test cases, careful consideration is given to the requirements definition. These test cases are often created from the working descriptions of the program, which may contain requirements, design criteria, and other specifications. The test designer will select both a favorable test scenario, in which the appropriate output is produced using legal input values, and an adverse test scenario, in which the correct output is determined using incorrect input values while running the test. Test cases have been created primarily to ease functional testing but are also malleable enough to accommodate non-functional testing. The testing team creates test cases, and the software development team plays no role. Software test engineers play an integral role in protecting the business and its product image from being ruined, and that is why employers pay them lucrative salaries. You can find about software test engineer salaries depending on location, skills, experience, etc, via multiple online sources. 

Types of Black Box Testing

Testing in a black box can be utilized for the following three primary categories: functional testing, non-functional testing, and regression testing.

Functional Testing:

• Testing in a black box enables testing of particular features or capabilities of the software being evaluated. For example, logging in using the wrong credentials is impossible, but you can log in safely with the correct details.
• Functional testing might focus on the essential features of the software being tested (also known as smoke testing or sanity testing), the integration between the software's essential components, or the system as a whole (system testing)..

Non-functional Testing: 

Beyond checking for features and operation, black box testing can look at other characteristics of the software as well. When doing a non-functional test, the focus is not on determining "whether" the program can carry out a particular activity but rather "how" it does so.

Tests known as black boxes can reveal whether or not the software is:

1. Accessible and straightforward to grasp for those that utilize it
2. capable of functioning well under average or peak loads
3. Compatible with hardware, screen dimensions, web browsers, and operating systems
4. Leaving themselves vulnerable to common security attacks or other security flaws

Regression Testing:

Black box testing helps determine the regression in an upgraded software version, generally defined as a decrease in capabilities from the previous version to the one being tested.  Both functional and non-functional component of software uses regression testing methods. One example of the former is when a newer version doesn’t work properly or correctly like the previous version (for example, a formerly fast operation becomes extremely slow in the new version).

The following are some techniques to black-box test design that are regularly used:

Test Design Techniques

The following is a list of approaches commonly used in black-box test design:

1. Decision table testing
2. All-pairs testing
3. Equivalence partitioning
4. Boundary value analysis
5. Cause–effect graph
6. Error guessing
7. State transition testing
8. Domain analysis
9. Syntax testing
10. Combining technique

Decision Table Testing: Decision tables are a condensed graphical representation that can be used to describe the actions to be carried out based on the conditions that have been provided. They are computer programs with the output of being a series of actions. The information in decision tables can also be represented as decision trees or written in a programming language as a series of statements that include if-then-else and switch-case.A predetermined group of criteria determines the outputs of many systems. The testers can then determine "rules," which are combinations of situations, determine the result of each rule, and construct a test case for each rule individually.

All-pair Testing: All-pair testing is a combinatorial approach of software testing that evaluates all conceivable discrete combinations of those parameters for each pair of input parameters to a system (usually a software algorithm). This method is also known as paired testing. By "parallelizing" the tests of parameter pairs and using test vectors that have been carefully selected, it is possible to complete this task much more quickly than by conducting a thorough search of all possible parameter combinations.

Equivalence Partitioning: In software testing, equivalence partitioning, also known as equivalence class partitioning (ECP), is a technique that partitions the input data of a software unit into equivalent data partitions, from which test cases can be produced. Test cases should generally be constructed to cover every partition at least once. 1. This technique attempts to design test cases that expose different problems to decrease the number of test cases that must be developed. One advantage of using this strategy is that it reduces the time required to test software because there are fewer test cases.Equivalence partitioning is generally conducted on the inputs of a tested component, but in some exceptional cases, it can also be performed on the component's outputs. In most situations, the equivalence partitions are derived from the requirements specification for input properties that influence the processing of the test object.

The core idea behind ECP originates from the concept of equivalence class, which originates from the concept of equivalence relation. In practical terms, a software system is a computable function encoded as an algorithm and written in some implementation programming language. When a test vector is provided as input, certain instructions of the algorithm will be covered while others will not. The following fascinating relationship emerges between the input test vectors as a result. A relation of equivalence, denoted by the symbol, exists between two test vectors, a and b, if and only if the coverage footprints of the vectors a and b are identical; that is if they cover the same instructions at the same step. Because of this, it is clear that the relation cover C will divide the domain of the test vector into more than one equivalence class. The equivalence class partitioning of test input describes this particular partitioning method. Suppose there are N classes that are equivalent to one another. In that case, you only need N vectors to cover the system.

Boundary Value Analysis: The software testing method known as boundary-value analysis involves designing tests to include values indicative of the range's boundaries. The boundary is where the concept originated. A topology can be defined based on that collection of test vectors, given that we already have a set of test vectors for testing the system. The basis would be comprised of inputs recognized by the equivalence partitioning theory to fall into the same equivalence class as one another. Because the basis sets are near one another, they might have a border. The boundary values are the values of the test vectors on each side of the border. For this to operate in practice, the test vectors must be rated, and the individual parameters must be put in some type of sequence (either partial or complete).

A cause-and-effect graph is a form of a directed graph that is used in software testing. This graph connects one group of causes to another set of consequences. One approach to conceive of the causes is as program input, and another way to think of the results is as program output. In a typical graph, the nodes representing the causes are located on the left side, and the nodes indicating the consequences are on the right. There may be intermediate nodes in between that mix the inputs using logical operators like AND and OR.

Error Guessing: Error guessing is a testing approach that is used in software testing, and it involves establishing test cases that are used to detect faults in programs based on knowledge gained from testing software in the past. The breadth of the test cases is typically determined by the software tester working on the project. This person draws on their prior knowledge and gut instincts to determine the scenarios that frequently result in software failure or have the potential to do so. Divide by zero, null pointers, and improper parameter values are examples of typical programming errors.

State Transition Testing: When some systems shift from one state to another, it can cause considerable responses to be generated within those systems. A typical illustration would be a login system that enables users to verify themselves but then moves to a new state that locks the account after a certain number of failed tries.Testers can build test cases to probe the system when transitioning between states if they first identify a state transition mechanism. For instance, if a system locks the account after five unsuccessful attempts to log in, a test case can investigate what occurs on the sixth occasion that the account is used to try to log in.

Our comprehensive guide on the top 122+ QA testing interview questions and answers, prepared under the guidance of industry experts, will be helpful for you to crack your QA testing interview. 

Domain Analysis: Domain analysis, also known as product line analysis, is a process used in software engineering that involves studying linked software systems in a domain to determine which components are shared and unique to each system. It is a model of the system's application in a broader business environment. James Neighbors is credited with first introducing the word in the early 1980s. The initial step in domain engineering is known as the domain analysis phase. It is an essential approach to methodically taking use of software reuse.

Tableau Testing Training

• Personalized Free Consultation
• Access to Our Learning Management System
• Access to Our Course Curriculum
• Be a Part of Our Free Demo Class

Sign Up Now

Conclusion

These are some basic concepts of black box testing and an overview of the approaches and procedures involved. Given that it is impossible to test everything with human involvement to one hundred percent accuracy, it is clear that the system's quality will increase if the tactics and methodologies outlined thus far are appropriately adopted. To summarize, this is a highly effective method for finding the majority of defects in the system and confirming system operation. After reading this blog you will be able to define black box testing or explain black box testing effectively.