What is Black Box Testing? | Techniques

Black box Testing Techniques

• • • • Equivalence partitioning.
      • Boundary Value Analysis
      • Decision table testing
      • State Transition Testing
      • Error Guessing

Advantages of Black-Box Testing

• • • • More effective on larger units of code than glass box testing
      • Tester needs no knowledge of implementation, including specific programming languages
      • Tester and programmer are independent of each other

Below is the overview of each black black box technique.

1) Equivalence partitioning

• • • It is also known as Equivalence Class Partitioning (ECP)
    • It is a specification-based or black-box technique
    • The input data is divided into different equivalence data classes – which are generally termed as ‘Valid’ and ‘Invalid’.
    • Test only one condition from each partition or equivalence.
    • It reduces the number of test cases to a finite list of testable test cases covering maximum possibilities

2) Boundary Value analysis

• • • Boundary value analysis is a selection of test cases that takes boundary values as inputs. It is based on the assumption that errors are usually found on boundaries.
    • It can be applied at all levels/phases of testing
    • Boundaries are good place to look for defects
    • Boundary Value Analysis is the next part of Equivalence Partitioning for designing test cases where test cases are selected at the edges of the equivalence classes.

3) Decision table testing

• • • A black-box test design technique in which test cases are designed to execute the combinations of inputs and their corresponding behaviour shown in a decision table.
    • It is referred to as a ’cause-effect’ table
    • Each column can then be considered as a test case of a business rule
    • Decision Table Testing is good for testing business rules or combinations
    • Contains conditions (Input) and actions (Outputs)

4) State Transition Testing

• • • A black box testing technique
    • State-transition diagrams are very useful for describing the behaviour of a system and are part of the Software Design Document.
    • Tests are designed to execute valid and invalid state transitions
    • State-Transition diagrams are an excellent tool to capture certain types of system requirements and to document internal system design.
    • This technique is used when features of a system are represented as states, which transform to another state.