Blackbox Test Design Techniques: Equivalence Partitioning and Boundary Value Analysis

Introduction

• Session: Part 1 of Session 3 of Module 4
• Topics Covered: Equivalence Partitioning and Boundary Value Analysis
• Test Design Techniques: Specification-based or Blackbox test design techniques

Equivalence Partitioning (EP)

Overview

• Type: Blackbox test design technique
• Applicable Levels: Unit, Integration, System, Acceptance
• Purpose: Divide test conditions into sets that are treated the same by the software

How It Works

1. Partitioning: Partition input data into valid and invalid partitions

   • Example: Text field accepting numbers 1 to 100
     • Valid Partition: 1-100
     • Invalid Partitions: <1 and >100

2. Design: Create test cases by testing one condition from each partition

   • Assumption: All values in a partition are treated similarly
   • Example: E-commerce discounts based on purchase amounts
     • No Discount: $0 to $50
     • 5% Discount: $50.01 to $200
     • 10% Discount: $200.01 to $500
     • 15% Discount: $500.01 to max
     • Invalid Partitions: Below $0 and Above max

Advantages

• Efficiency: Reduces number of test cases needed
• Coverage: Ensures better coverage of possible input scenarios

Boundary Value Analysis (BVA)

Overview

• Type: Blackbox test design technique
• Purpose: Test the behavior of software at the boundaries of equivalence partitions

How It Works

1. Identify Boundaries: Test cases are created using boundary values

   • Example: Text field accepting 1 to 1000
     • Valid Partition: 1-1000
     • Invalid Boundaries: 0, 1001

2. Minimum and Maximum Values: Select minimum and maximum from valid partitions

   • Example: For the range $0 to $50, boundary values are 0 and 50

Advantages

• Edge Testing: Focuses on values at the edge where software is likely to fail

Combining EP and BVA

Why Combine?

• Comprehensive Testing: Testing boundaries alone or partitions alone is not sufficient
• Structured Approach: Ensures thorough testing by covering both partitions and edges

Best Practices

1. Separate Testing: Test partitions separately from boundaries
2. Test Order: Start with valid partitions, then invalid partitions, then valid boundaries, and finally invalid boundaries
3. Thorough Testing: Incorporate both techniques in test design

Conclusion

• Learnings: Specification-based test design, Equivalence Partitioning, Boundary Value Analysis
• Importance: These techniques streamline the testing process and ensure comprehensive test coverage
• Efficiency: Using EP and BVA together helps in effectively covering all aspects of the software with reduced effort

Thank you!