Black Box Testing

1
Black Box Testing

• SE 452, Software Verification and Validation
• Mark Ardis, RIT

2
Black Box Testing

• Use only specification of program
• Test implementation against its specification

3
Black Box Methods

• Equivalence partitioning
• Boundary value analysis

4
Equivalence Partitioning

• Look for partitions of input space
• assume that all values within the partition are
  equivalent
• assumes that testing any single value finds any
  error for that partition
• Create representative values for each partition

5
Triangle Program Example

• Input consists of 3 integers
• Each input represents the length of a side of the
  triangle
• Output states whether the triangle is
• equilateral (all 3 sides equal)
• isosceles (2 equal sides)
• scalene (different length sides)
• invalid (cannot be a triangle)

6
Example Partitions

• 2, 2, 2 (equilateral)
• 2, 2, 3 (isosceles)
• 2, 3, 4 (scalene)
• 2, 3, 6 (invalid)

7
Boundary Value Analysis

• Examine boundary values of specification
• Create tests on each side of each boundary (valid
  and invalid)

8
Example Boundaries

• 1, 1, 1 (minimum valid values)
• 1, 0, 1 (invalid too small)
• 20, 30, 49 (valid)
• 20, 30, 50 (invalid one side equals
  sum of other two sides)
• 20, 30, 51 (invalid one side too long)