Black box testing is an essential practice in software development companies that helps you find bugs and errors before they cause serious problems.
This method can be implemented by using several different approaches, and choosing the most suitable method depends on your specific project.
In this guide, you will get an overview of what the black box method is, types of black box testing, how it's used and why it's so important; as well as describe some of the various black box testing methods available to you so you can choose the best strategy for your needs.
Table of Contents
What Is Black Box Testing?
In software testing, black box testing is a method in which the test engineers do not have any knowledge of the program's inner workings. It is one of the oldest software development techniques and it's has been around since the mid-1950s.
This form of testing focuses on the inputs and expected outputs based on defined requirements. It means that you don't need to know how your application works internally while writing test cases.
The black box method aims to test the software's functionality without looking at the program's source code or any other implementation details.
This testing class focuses on the program's inputs and outputs, not its internal workings.
This makes it an excellent option to be used alongside unit testing or white box testing. Both types of testing will ensure that you have tested your software from all possible angles. Also, it ensures that it works and operates as expected throughout its lifecycle.
How Are Black Box Testing Techniques Done?
Black box testers use specific tools to perform their assessments on programs during testing sessions.
These tools allow them to access information about an application's source code, but not its internal workings at run time (i.e., when it executes).
Black box testing involves three steps:
- Identify requirements for your software application (e.g., what functionality should it provide?).
- Create mock-ups for each feature you plan to add to your product and any supporting documentation such as user stories and acceptance criteria (if appropriate).
- Perform functional tests against these mock-ups.
Black box testing techniques are usually done by software development or software testing agencies that do not know the internal structure of the software being tested.
To test the software's functionality, they will use input values and analyze the output values to see if they meet the expectations.
The black box method can test all types of software, including web applications, desktop applications, and mobile apps.
What Are the Advantages of Black Box Testing Methods?
Although many different types of software testing exist, one often overlooked by developers and testers alike is black box testing.
The black box method is beneficial because it's easy to automate, meaning you don't have to set up any extra tools or platforms. You just need a computer with an internet connection and some programming knowledge. Or you can hire a professional black box tester, like what 35% of companies do, according to study.
Black box testing techniques also allow you to test complex systems in ways that are not possible with white box testing because the tests are not limited by the specific features of your product (or other factors).
Here are some of the reasons why it's beneficial:
- Black box testing can help you find hidden errors and defects in your software that you would not have found otherwise.
- It can save you time and money by helping you find defects early in the development process.
- It can improve the quality of your software by helping you find and fix defects before your customers do.
- Also, it can increase customer satisfaction by helping you deliver a higher quality product.
- Black box testing techniques can help you meet deadlines by helping you find and fix defects quickly.
- Black box testing methods can improve the usability of your software by helping you find and fix usability issues.
Types of Black Box Testing
The tester is only concerned with the inputs and outputs of the system. Black box testing can test various aspects of the software, including usability, compatibility, and performance. These are the most common types:
1. Functional Testing
Functional testing is a type of black box testing. It checks the application's functions, such as user interface, business logic, and database access.
These tests are performed by testers or programmers and may be done manually or automatically by tools.
Functional testing can be performed in two ways:
- Manual functional testing: A tester performs each feature individually to verify that it works as expected before moving on to the next feature
- Automated functional testing: An automated tool runs through all features under test without human intervention (for example, Selenium).
2. Non-Functional Testing
If black box testing is used to test more aspects other than functionality and features, it falls under the category of “non-functional” testing.
Non-functional testing examines how well the system does its job—whether or not the software functions correctly in all conditions.
For example, if it's capable of functioning at peak efficiency and compatible with different devices (including mobile).
Here are some types of non-functional testing:
- Usability testing is vital to ensure users can use the system. This test focuses on the user interface and user-friendliness.
- Compatibility testing is essential to make sure that the system works with different types of hardware and software. This includes things like operating systems and browsers.
- Performance testing ensures that the system can handle high loads. This includes things like stress tests and load tests.
3. Regression Testing
When you add new programs or code to an old one, Regression testing ensures that all bugs are taken care of.
According to research, 78% of organizations automated tests for regression testing.
It goes through the already-executed programs to ensure they're not malfunctioning; this is done by going through complete or partial test cases while checking for abnormalities.
There are three popular Regression testing tools - Selenium, QTP (Quick Test Professional), and Rational Functional Tester - which work best depending on what type of company you work for.
Black Box Testing Techniques
There are many different types of black box testing techniques, including:
- Error Guessing
- Orthogonal Array Testing
- All-Pairs Testing
- Equivalence Partitioning
- Boundary Value Analysis
- Decision Table Testing
1. Error Guessing
Error guessing is a black box testing technique. It is also called "fault guessing."
This kind of testing is a form of white box testing, where we have to guess what might be wrong with our software product.
In this case, we don't know if there are any bugs in the program; instead, we need to find out whether there are any bugs by looking at the output produced by our program and then make some assumptions based on this output.
2. Orthogonal Array Testing
Orthogonal Array Testing is a type of Black Box Testing that involves generating test data at random. The test data is chosen randomly and not based on any prior information about the system being tested.
The chief advantage of this approach is that it ensures that every possible configuration will be tested, which can help you identify bugs or issues in your product's design before they become apparent during regular operation.
3. All-Pairs Testing
All-Pairs testing is a type of black box testing used to test the software by trying all possible pairs of inputs. It can be applied to hardware and software, and it's often used when you want to test communication protocols involving multiple interactions between components in the system.
The idea behind all-pairs testing is that you're trying out every combination of input data that your program could receive or send.
4. Equivalence Partitioning
Testers can divide up potential inputs into groups, called partitions.
It is sufficient for testers to provide an input example from only one partition (for instance, the under 18 group) when there is consistency in results across all other divisions.
Likewise, it would be enough for a tester to check only over 18 partitions if there were variances in responses within the other groups.
5. Boundary Value Analysis
A testing technique where tapers focus on how well a system behaves near boundaries of its valid range values such as at 0 and 100 as opposed to edges (0-1).
6. Decision Table Testing
Many systems require outputs based on given sets of conditions. Testers will list out these rules, identifying the exact result for each rule pair before designing tests that show whether the expected behavior was observed or not.
What Are the Disadvantages of Black Box Methods?
The main advantage of black box testing is that it helps identify bugs in your code before you have time to fix them yourself.
However, this method can also be problematic because there may be bugs that aren't detected during this testing but would still exist after fixing all known issues within your program.
Here are a few things to consider when using black box testing techniques:
- You can't test certain things. For example, you can't test for usability with black box testing.
- It’s time-consuming. You must figure out what inputs to use and what outputs to expect.
- It’s not thorough. Black box testing only tests the functionality of the system, not the internal code or structure.
- It can be expensive. If you need to hire testers, it can be costly.
- It requires documentation.
Black Box Testing: Final Thoughts
Black box testing allows for a detailed examination of how software behaves regarding accuracy, usability, and other features. This type of testing provides an overview of how well the program operates.
Black box testing also increases the rate at which developers can publish new versions while reducing the likelihood that errors will appear later in production.
This process minimizes risk, so users are less likely to experience problems using your product or service.
