Top 5 Black Box Testing Techniques You Need to Know

Both beginners and experienced QA professionals should refresh their knowledge about the testing techniques. In this post, we’ve collected the basic facts and concepts about black box testing, its main types, techniques, and methods. In case you want to know more about this topic, get ready to dive into the world of black box testing fundamentals collected all in a single post.

The basics of black boxing

First of all, let’s find out what are the main concepts. The black box tests are monitoring and examining a particular system from the customer’s perspective. This type of QA effort is based on input and output data when you don’t focus on details such as logic, code, and other development parameters. In other words, black box testing is verifying whether the solution validates against a list of predesigned parameters but without knowing the internal structure of the product prior to testing.

Performing these tests doesn’t involve checking code or exploring various internal system’s parameters. The only thing a QA expert should do is to compare the actual inputs with the received outputs. To make testing successful, a quality assurance engineer should be familiar with advanced system requirements rather than its internal functionality.

Black box and white box testing: what is the difference?

Unlike black box testing, performing white box test cases requires a profound knowledge of coding and the internal structures of the solution. White box testing is done from the viewpoint of a skilled developer but not from the viewpoint of a common user. This is the reason that some call it ‘code base testing’. Thus, white box testing might include operations that a real user could never perform.

Black box testing is designed to check a list of different parameters such as:

• Problems with usability
• Precise actions made by common users
• Performance issues
• Program’s failures to start or finish
• The time the system requires to response

Black box testing offers a great number of advantages. Although this is a common technique used by QA experts for years, it still remains to be extremely effective.

The benefits of black box testing techniques:

• Allows checking the program’s usability easily and quickly
• Gives a broad picture of the tested application
• Enables tester to perform tests from the user’s side
• Allows testing the whole solution with no need to test its different blocks
• A QA with no technical background can perform the tests in an effective way
• The test cases can be performed after the development stage
• Tests can be performed outside the organization by an external team of testers (crowd testing or outsourcing) 

Top 5 black boxing techniques for QA professionals

There are dozens of black boxing methods used by different QA Engineers. We’ve collected a list of the most popular and powerful ones for an effective quality assurance process.

Exploratory testing

This type of testing is developed to simulate the user’s behavior. A QA professional simulates the user’s actions to check various types of system’s functionality. The tester should know exactly the system’s response to different actions with no need to check its code. In other words, a QA expert should make tests “wearing the user’s feet but with a tester’s hat”. This technique is ideal for crowd testing to allow many testers to simulate the user behaviour. 

State transition testing

This type of QA effort is performed in environments that might have different outputs for the same kind of input. This means their behavior depends not only on input parameters but on some external features. For example, a cash machine will give you $10 when you have this sum of money on your account but will refuse to give you money when you have a $0 balance. The system “transitions” to various states. The tester should check all types of the system’s states during transition testing.

Boundary value analysis

This analysis is performed when the tester needs to check the behavior of a certain system within the predefined borders. The technique determines whether a certain range of values are accepted by the system or not.  For example, in case your system accepts only numbers between 900 and 1000, you will not need to check the entire range of numbers between these borders. The tester will only test the response of the system on 900 and 1000 (as well as 1001)

Use case testing

This type of testing is designed to check all the test cases used in a certain environment. It tracks all testing scenarios and helps to review all the functions in a system from their start to finish.

Error guessing

The parameters for performing this technique depend on the experience of the tester. QA professionals usually know the weak points of the systems, as well as the places where mistakes and errors often occur. Moreover, with an error guessing method, testers usually check the most common system’s vulnerabilities. For example, they can review the system’s output when the user is trying to upload a file without an attachment or enter the wrong captcha.

How to perform black-box testing?

1. Check the requirement specifications of the system under tests. It is a great advantage to use SRS (Software Requirements Specification) documents at this stage.
2. Determine the inputs (positive and negative) for performing tests to get the best possible test coverage
3. Prepare the test cases to check all the required parameters and execute the test cases.
4. Check the system’s outputs (actual Vs. expected) and detect the failing ones
5. Provide the developers the information about errors and failures and wait for them being fixed
6. Make a full list of tests prepared in point 3 of this list and check all the outputs once again (retest)

Ubertesters QA services and Black Box testing

Ubertesters offers a fast, flexible and cost effective method to scale the organization’s black box testing requirements. Ubertetsers provides access to a large community of professional QA experts that can successfully execute any type of black box testing, while providing great results about the product’s quality and ability to meet user’s expectations.   

The black box techniques are a perfect solution to monitor the systems where the functionality and user-friendly design have a higher value than clear code. Want to know more about the opportunities of black boxing offered by Ubertesters?

Feel free to contact us at sales@ubertesters.com