Methods of Black box Testing

The following basic techniques are employed during black box testing:

• Equivalence Class
• Boundary Value Analysis
• Error Guessing

Equivalence Class:

• For each piece of the specification, generate one or more equivalence Class
• Label the classes as “Valid” or “Invalid”
• Generate one test case for each Invalid Equivalence class
• Generate a test case that covers as many Valid Equivalence Classes as possible

An input condition for Equivalence Class:

• A specific numeric value
• A range of values
• A set of related values
• A Boolean condition

Equivalence classes can be defined using the following guidelines:

• If an input condition specifies a range, one valid and two invalid equivalence class are defined.
• If an input condition requires a specific value, one valid and two invalid equivalence classes are defined.
• If an input condition specifies a member of a set, one valid and one invalid equivalence classes are defined.
• If an input condition is Boolean, one valid and one invalid classes are defined.

Boundary Value Analysis

• Generate test cases for the boundary values.
• Minimum Value, Minimum Value + 1, Minimum Value -1
• Maximum Value, Maximum Value + 1, Maximum Value – 1

Error Guessing.

• Generating test cases against to the specification.

Go back to Test Design Techniques