What is Black Box Testing? Its Types and How To Do It?

A wide range of security and quality testing methods are used in the software development phase. And black box testing is among the most common application security testing methods used by businesses to ensure that the products they release are safe, protected, and of excellent quality. One of the most significant advantages of black box testing is that you can use it at all levels of testing. Anyone with little or no coding knowledge and software testers with no coding knowledge can perform black box testing on a software product.

So, what exactly is black box testing? Before we answer this question, let’s go over the topics we’ll be covering in this blog:

• What is black box testing?
• Example of black box testing
• Features of black box testing
• What are black boxes test cases like – Types of black box testing
• Black Box Testing techniques 
• Where can we use black box testing?
• How to do black box testing?
• Tools for black box testing
• Black Box Testing in Software Engineering – Software Testing Life Cycle
• Advantages of black box testing
• Disadvantages of black box testing
• Black box vs. white box testing?
• Conclusion

What is Black Box Testing? 

Black Box Testing, also known as Function Testing, is a powerful technique to test the functionalities of software applications without an in-depth understanding of the internal logic or source code of the software. In a nutshell, “black box testing is a technique that examines software’s functionality without examining its internal structure or coding.”

Behavioral testing and specifications-based testing are other terms for black box testing. Black box testing effectively determines whether a system’s design meets requirements and avoids implementation errors. In black box testing, you check the output for a given input to see if the software meets the specifications.

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Examples of Black Box testing 

Let’s have a look at some of the behavioral testing examples:

For smooth user login, suppose you want to test a simple login screen of the software. As input, the login screen has two fields, username, and password, and the output will be system access. A black box testing will not consider the code specifications and will examine both the input and output, such as: Users are logged in when they enter a valid username and password. On the other hand, an error message is displayed when a user enters an incorrect username and password.

The main objective of this type testing will be to examine scenarios in which the system could fail. For example, a user may enter the password in the incorrect format and may not receive an error message when doing so.

Features of Black Box testing

There are various features of this type of testing, and some of those features are:

• It is unnecessary to be familiar with the software or its internal architecture.
• Testers can work independently of developers, ensuring unbiased and end-user-focused testing.
• This type of testing examines both the application’s functional and non-functional requirements.

What are Black Boxes Test Cases Like – Types of Black Box Testing 

This type of testing is of three types: functional testing, non-functional testing, and regression testing.

• Functional testing: This type of testing examines a specific function or feature of the software. For example, if you enter the correct pin in the Gpay app, the transaction goes through, but if the incorrect pin is entered, the transaction fails. Unit testing, smoke testing, and other common examples of functional testing
• Non-functional testing: This type of testing examines more aspects of a software’s functionality and features. With the help of this type of testing, you can determine whether the software can withstand high loads and is compatible with various devices.
• Regression testing: This testing involves testing the software after code fixes, upgrades, or other system maintenance to ensure that the new changes have not affected any existing functionality.

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Where can we use Black Box testing?

In some ways, we’ve all used behavioral testing daily. Consider your automobile. When you wish to start your car, you press the start button and wait for it to begin. In either case, you usually don’t have a detailed knowledge of what occurs inside the car to start it. The car is similar to a non-transparent box whose inner workings you are unaware of. You can’t look through the outer shell of a black box to see what’s inside. Hence, the use of behavioral testing is enormous, and knowingly or unknowingly, we keep using behavioral testing even in our daily lives.

In software testing, behavioral testing can be used for various purposes, including checking and validating the entire software development life cycle or evaluating the software or a product at different phases such as unit, assimilation, acknowledgment, system, and regression.

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Black Box Testing techniques 

There are various behavioral testing techniques, such as shown in the image below:

Now, let’s go through some of the techniques that are most popular:

Boundary value analysis

This technique puts the software through its paces using test cases with extreme test data values. For example, assume you have a piece of software that requires you to enter your age with a valid range of 1-100. The software will be tested against boundary values such as 1, 100, and 101 in order to assess the system’s response.

Equivalence partitioning

This technique compares input and output by categorizing the input. This technique ensures complete data coverage during testing. Assume you have a piece of software that requires you to enter your age, with a valid range of 1-100. The software will be tested using this technique based on the number of valid classes. In this case, there will be three valid classes: any number (1 to 100), -1 (checking the lowest of the lowest), and 101 (checking the lowest of the lowest) (highest of highest).

State transition testing

This technique tests software based on the inputs, outputs, and system state during the testing phase. For example, a login page will allow you to enter your username and password up to three times. The user will be directed to the login page for each incorrect password. The user will be directed to an error page after the third attempt. This state transition method considers the various system states and inputs in order to pass only the correct testing sequence.

Decision table testing

This technique is based on a decision table. A decision table is a matrix that contains the causes and their effects. Each column contains a distinct combination. An online food app, for example, will verify various payment options as input to place an order — table-based decision-making.

• Case 1: If the end-user has a card, the software will not check for cash or a coupon and will proceed with the order.
• Case 2: If the end-user has a coupon, no card or cash will be checked, and action will be taken.
• Case3: If the end-user has cash, action will be taken.
• Case 4: If the end-user has nothing, no action will be taken.

How to do Black Box Testing? 

Here are the steps that you need to perform:

1. Understand the application under the test’s requirement specifications. A precise and accurate SRS document should be present. (A Software Requirements Specification (SRS) document outlines what the software will do and how it should perform.)
2. To test the software, evaluate the set of valid inputs and test scenarios.
3. Prepare the test cases to cover as many inputs as possible.
4. Run the test cases in the system to generate output validated against the expected outcome to determine whether the test passes or fails. The failed steps are noted and forwarded to the development team for correction.
5. Based on the defects that have been fixed, the tester retests the defects to determine whether or not they are recurring.

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Tools for Black Box testing

The most advantageous aspect of this type of testing is its ability to be performed using a variety of automated tools, which simplify and improve the process’s accuracy. Recording and playback tools are generally preferred with Java, Visual Basic, and Perl. However, other behavioral testing tools are also used by various black box testers, such as:

• Appium
• HP QTP
• Selenium
• Applitools
• Microsoft Coded UI

Black Box Testing in Software Engineering – Software Testing Life Cycle

Behavioral testing has a life cycle known as the Software Testing Life Cycle (STLC). The STLC is divided into six phases, such as:

• Requirement analysis: In this phase, the feature requirements gathered during the SDLC process are analyzed in order to identify testable aspects.
• Test planning: The test strategy is outlined in a test plan document during this phase. This strategy outlines the tools required, the testing steps, and the roles and responsibilities.
• Test case development: Test cases are created during this phase. Each case specifies the test inputs, procedures, execution conditions, and expected outcomes.
• Configuration and deployment of testing environments: During this phase, testing environments are configured and deployed.
• Execution of test cases: During this phase, features are tested in the deployed environment using the established test cases.
• Test cycle closure: The final phase of the STLC in which a test result report is prepared.

Advantages of Black Box Testing 

Some of the advantages of this type of testing are:

• When used on large systems, this type of testing is efficient.
• Testing assists in identifying ambiguities and contradictions in functional specifications.
• Once the software needs and specifications are defined, test cases and scenarios can be created.
• Both development and testing are separated, allowing for a more objective approach and reducing bias.
• Because testing is performed from the end user’s perspective, testers are not required to have any technical knowledge of programming or how the software is implemented.

Disadvantages of Black Box testing

Some of the disadvantages of this type of testing are:

• If the development or design team has already performed tests, behavioral testing may be unnecessary.
• The number of possible inputs that can be verified is limited because a thorough testing procedure of the entire software program can be time-consuming.
• Because black box tests depend on software requirements and specifications, they must be well defined ahead of time. Otherwise, creating test cases becomes extremely difficult.

Black box vs. white box testing? 

White Box testing is a technique that examines the underlying structure, layout, and coding of software. This is done to ensure that the input-output flow is correct and to improve design, functionality, and stability. Because code is visible to testers during white box testing, it is also known as clear box testing, open box testing, glass box testing, code-based testing, or transparent box testing.

Let’s go over the differences between behavioral testing and white box testing using the image below:

Must explore: Difference between Black box and White box testing

Conclusion

The behavioral testing technique is critical in testing digital products from the perspective of end users in order to ensure a flawless user experience. Behavioral testing allows you to focus not only on quality assurance and functional testing but also on non-functional testing, such as usefulness.