What is Black Box Testing? Why do we need Black Box Testing | Tutorial with Examples | InterviewDOT
Channel: Interview DOT
Date: 2020-03-17

Click here - https://www.youtube.com/channel/UCd0U_xlQxdZynq09knDszXA?sub_confirmation=1 to get notifications.

Tamil What is Black Box Testing? Tutorial with Examples| InterviewDOT

What is Black Box Testing?
BLACK BOX TESTING is defined as a testing technique in which functionality of the Application Under Test (AUT) is tested without looking at the internal code structure, implementation details and knowledge of internal paths of the software. This type of testing is based entirely on software requirements and specifications. In BlackBox Testing we just focus on inputs and output of the software system without bothering about internal knowledge of the software program.

How to do BlackBox Testing
Here are the generic steps followed to carry out any type of Black Box Testing.

Initially, the requirements and specifications of the system are examined.
Tester chooses valid inputs (positive test scenario) to check whether SUT processes them correctly. Also, some invalid inputs (negative test scenario) are chosen to verify that the SUT is able to detect them.
Tester determines expected outputs for all those inputs.
Software tester constructs test cases with the selected inputs.
The test cases are executed.
Software tester compares the actual outputs with the expected outputs.
Defects if any are fixed and re-tested.

Types of Black Box Testing
There are many types of Black Box Testing but the following are the prominent ones -

Functional testing - This black box testing type is related to the functional requirements of a system; it is done by software testers.
Non-functional testing - This type of black box testing is not related to testing of specific functionality, but non-functional requirements such as performance, scalability, usability.
Regression testing - Regression Testing is done after code fixes, upgrades or any other system maintenance to check the new code has not affected the existing code.

Black Box Testing Techniques
Following are the prominent Test Strategy amongst the many used in Black box Testing

Equivalence Class Testing: It is used to minimize the number of possible test cases to an optimum level while maintains reasonable test coverage.
Boundary Value Testing: Boundary value testing is focused on the values at boundaries. This technique determines whether a certain range of values are acceptable by the system or not. It is very useful in reducing the number of test cases. It is most suitable for the systems where an input is within certain ranges.
Decision Table Testing: A decision table puts causes and their effects in a matrix. There is a unique combination in each column.