What is BLACK Box Testing? Techniques, Example & Types
What is Black Box Testing?
Black Box Testing is a way of testing software’s functionalities without any prior knowledge of its internal code structure, internal paths and implementation details. The tester enters an input and analyses the output generated by the software. Hence, the response of the software to user actions, its response time, reliability and usability issues can be identified. The testing process is also known as Behavioral Testing.
It is considered a powerful testing technique due to its ability to analyse a system end-to-end. UI/UX, database, web server or application server, dependencies and integrated systems are evaluated in black box testing.
How to conduct Black Box Testing?
The conventional steps to be followed for Black Box Testing are:
- The system specifications and requirements are evaluated
- Some valid inputs are entered and it is checked whether the SUT responds to it correctly. Few invalid inputs are also chosen to ensure that SUT is able to detect them as well
- The expected outputs for those inputs are determined
- Test cases corresponding to the selected inputs are determined
- Test cases are executed
- The actual outputs and expected outputs are compared
- In case of defects, the code is fixed and re-checked.
Types of Black Box Testing
This type of testing is used to test specific features or functions of the software of which the test is being undertaken. It focuses on the most critical aspects of the software and the key components.
Non-Functional Testing is done to test the non-functional requirements of the software like usability, performance and scalability. Instead of checking ‘if’ the system responds to a particular action, it checks ‘how’ it responds. It checks the ease with which the software understands the user, its performance under peak load, compatibility with devices and security threats.
This type of testing is conducted after undertaking code fixes, upgrades and system maintenance to check if the system exhibits any degradation in capabilities or regression. It checks if the new code has affected the existing code in any way.
Black Box Testing Techniques
In this technique, the possible inputs are grouped together. So, the number of possible test cases reduced to optimal level and test coverage is also reasonable.
Boundary Value Analysis
With the help of boundary value analysis, a tester can detect if a software displays a special response around a specific boundary value. It is a useful technique to reduce the number of test cases and most suitable for software where the inputs lie within a particular range.
Decision Table Testing
The output is based on a set of conditions for many systems. With this technique, the rules followed by the systems to generate the output can be identified. Therefore, the tester can comprehend the outcome of each rule and design a corresponding test case for each rule.
State Transition Testing
In some systems, when the system transits from one state to another, a significant number of responses are generated. The tester detects the state transition mechanism and design tests accordingly, The test cases probe the system when it transits from one state to another.
This technique is aimed at testing for the common errors made by developers during building the similar system. One specific kind of error guessing is testing for known software vulnerabilities. It is checked if the system is prone to be attacked using those vulnerabilities.
Black Box Testing Tools:
As per the type of black box testing you are doing, the type of tool differs.
Functional Tests – UFT, Tricentis Tosca, TestComplete, Selenium
Non-Functional Tests- LoadRunner, Forecast,Jmeter, Load Complete, Loadster Regression Tests – Selenium, IMB Rational Functional Tester, Watir, TestDrive.
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