BLACK BOX TESTING: BOUNDARY VALUE ANALYSIS AND EQUIVALENCE PARTITIONING

PROBLEM 1: DISCOUNT CALCULATION ON PURCHASE

Problem Statement

A discount is offered on purchases as follows:

| Purchase Range | Discount Percentage |

| 1000 Rs to 5000 Rs | 10% |

| 5001 Rs to 10000 Rs | 20% |

| Above 10000 Rs | 25% |

Equivalence Classes

Valid Classes:

- VC1: Purchase amount 1000 to 5000 Rs → 10% discount

- VC2: Purchase amount 5001 to 10000 Rs → 20% discount

- VC3: Purchase amount above 10000 Rs → 25% discount

Invalid Classes:

- IC1: Purchase amount < 1000 Rs → No discount (0%)

- IC2: Purchase amount = 0 Rs → Invalid

- IC3: Purchase amount < 0 Rs → Invalid (Negative value)

- IC4: Non-numeric input → Invalid

Boundary Value Analysis

Boundaries Identified:

- Lower boundary of VC1: 1000 Rs

- Upper boundary of VC1: 5000 Rs

- Lower boundary of VC2: 5001 Rs

- Upper boundary of VC2: 10000 Rs

- Lower boundary of VC3: 10001 Rs

Boundary Values:

- Just below 1000: 999 Rs

- At boundary 1000: 1000 Rs

- Just above 1000: 1001 Rs

- Just below 5000: 4999 Rs

- At boundary 5000: 5000 Rs

- Just above 5000: 5001 Rs

- Just below 10000: 9999 Rs

- At boundary 10000: 10000 Rs

- Just above 10000: 10001 Rs

Test Cases

| TC1 | 0 | 0% | Invalid/No Discount | Boundary | Zero value |

| TC2 | -500 | 0% | Invalid | Boundary | Negative value |

| TC3 | 999 | 0% | No Discount | BVA | Just below minimum |

| TC4 | 1000 | 10% | 900 Rs final | BVA | Lower boundary VC1 |

| TC5 | 1001 | 10% | 900.90 Rs final | BVA | Just above lower boundary |

| TC6 | 3000 | 10% | 2700 Rs final | EP | Middle value VC1 |

| TC7 | 4999 | 10% | 4499.10 Rs final | BVA | Just below upper boundary |

| TC8 | 5000 | 10% | 4500 Rs final | BVA | Upper boundary VC1 |

| TC9 | 5001 | 20% | 4000.80 Rs final | BVA | Lower boundary VC2 |

| TC10 | 7500 | 20% | 6000 Rs final | EP | Middle value VC2 |

| TC11 | 9999 | 20% | 7999.20 Rs final | BVA | Just below upper boundary |

| TC12 | 10000 | 20% | 8000 Rs final | BVA | Upper boundary VC2 |

| TC13 | 10001 | 25% | 7500.75 Rs final | BVA | Lower boundary VC3 |

| TC14 | 15000 | 25% | 11250 Rs final | EP | Middle value VC3 |

| TC15 | 50000 | 25% | 37500 Rs final | EP | Large value VC3 |

| TC16 | ABC | Error | Invalid Input | EP | Non-numeric |

| TC17 | 2500.50 | 10% | 2250.45 Rs final | EP | Decimal value |

Calculation Examples

Example 1: Purchase = 5000 Rs

- Discount = 10% of 5000 = 500 Rs

- Final Amount = 5000 - 500 = 4500 Rs

Example 2: Purchase = 10001 Rs

- Discount = 25% of 10001 = 2500.25 Rs

- Final Amount = 10001 - 2500.25 = 7500.75 Rs

PROBLEM 2: LIFE INSURANCE PREMIUM RATES

Problem Statement

Life Insurance Premium rates based on age:

| Age Group | Premium (Rs) |

| Under 35 | 2000 |

| 35-59 | 5000 |

| Above 60 | 10000 |

Equivalence Classes

Valid Classes:

- VC1: Age 0 to 34 → Premium 2000 Rs

- VC2: Age 35 to 59 → Premium 5000 Rs

- VC3: Age 60 and above → Premium 10000 Rs

Invalid Classes:

- IC1: Age < 0 → Invalid (Negative age)

- IC2: Age > 120 → Invalid (Unrealistic age)

- IC3: Non-numeric input → Invalid

Boundary Value Analysis

Boundaries Identified:

- Upper boundary of VC1: 34 years

- Lower boundary of VC2: 35 years

- Upper boundary of VC2: 59 years

- Lower boundary of VC3: 60 years

Boundary Values:

- Just below 35: 34 years

- At boundary 35: 35 years

- Just above 35: 36 years

- Just below 60: 59 years

- At boundary 60: 60 years

- Just above 60: 61 years

Test Cases

| TC2 | 0 | 2000 | BVA | Newborn |

| TC3 | 1 | 2000 | EP | Child |

| TC4 | 18 | 2000 | EP | Young adult |

| TC5 | 25 | 2000 | EP | Middle of VC1 |

| TC6 | 33 | 2000 | BVA | Just below boundary |

| TC7 | 34 | 2000 | BVA | Upper boundary VC1 |

| TC8 | 35 | 5000 | BVA | Lower boundary VC2 |

| TC9 | 36 | 5000 | BVA | Just above boundary |

| TC10 | 45 | 5000 | EP | Middle of VC2 |

| TC11 | 50 | 5000 | EP | Middle of VC2 |

| TC12 | 58 | 5000 | BVA | Just below boundary |

| TC13 | 59 | 5000 | BVA | Upper boundary VC2 |

| TC14 | 60 | 10000 | BVA | Lower boundary VC3 |

| TC15 | 61 | 10000 | BVA | Just above boundary |

| TC16 | 70 | 10000 | EP | Senior citizen |

| TC17 | 80 | 10000 | EP | Very senior |

| TC18 | 100 | 10000 | EP | Centenarian |

| TC20 | ABC | Error/Invalid | EP | Non-numeric |

Decision Table

| Age < 0 | Yes | No | No | No |

| 0 ≤ Age < 35 | No | Yes | No | No |

| 35 ≤ Age < 60 | No | No | Yes | No |

| Age ≥ 60 | No | No | No | Yes |

| Action | Invalid | 2000 Rs | 5000 Rs | 10000 Rs |

PROBLEM 3: ELECTION VOTING ELIGIBILITY

Problem Statement

Election voting rules:

| Age Group | Voting Status |

| 0 to 17 | Not eligible |

| 18 and above | Eligible |

| Negative age | Not eligible (Invalid) |

Equivalence Classes

Valid Classes:

- VC1: Age 0 to 17 → Not eligible

- VC2: Age 18 and above → Eligible

Invalid Classes:

- IC1: Age < 0 → Invalid/Not eligible

- IC2: Age > 150 → Invalid (Unrealistic)

- IC3: Non-numeric input → Invalid

Boundary Value Analysis

Boundaries Identified:

- Upper boundary of VC1: 17 years

- Lower boundary of VC2: 18 years

Boundary Values:

- Just below 18: 17 years

- At boundary 18: 18 years

- Just above 18: 19 years

Test Cases

| TC3 | 0 | Not eligible | BVA | Newborn |

| TC4 | 1 | Not eligible | EP | Infant |

| TC5 | 10 | Not eligible | EP | Child |

| TC6 | 15 | Not eligible | EP | Teenager |

| TC7 | 16 | Not eligible | BVA | Just below boundary |

| TC8 | 17 | Not eligible | BVA | Upper boundary VC1 |

| TC9 | 18 | Eligible | BVA | Lower boundary VC2 (exact) |

| TC10 | 19 | Eligible | BVA | Just above boundary |

| TC11 | 25 | Eligible | EP | Young adult |

| TC12 | 50 | Eligible | EP | Middle-aged |

| TC13 | 75 | Eligible | EP | Senior citizen |

| TC14 | 100 | Eligible | EP | Centenarian |

| TC15 | 120 | Eligible | EP | Very old |

| TC17 | 17.9 | Not eligible | BVA | Decimal just below |

| TC18 | 18.0 | Eligible | BVA | Decimal at boundary |

| TC19 | 18.1 | Eligible | BVA | Decimal just above |

| TC20 | XYZ | Error/Invalid | EP | Non-numeric |

| TC22 | " " | Error/Invalid | EP | Empty/space |

Decision Table

| Age < 0 | Yes | No | No |

| 0 ≤ Age ≤ 17 | No | Yes | No |

| Age ≥ 18 | No | No | Yes |

State Transition Diagram

[Not Eligible] ------Age reaches 18------> [Eligible]

^ |

| |

+---------Age drops below 18--------------+

(Invalid scenario)

COMPARISON: BOUNDARY VALUE ANALYSIS vs EQUIVALENCE PARTITIONING

| Aspect | Boundary Value Analysis | Equivalence Partitioning |

| Focus | Boundaries between partitions | Representative values from partitions |

| Test Cases | Tests at, just above, just below boundaries | Tests one value from each partition |

| Coverage | Focuses on edge conditions | Focuses on typical conditions |

| Defect Detection | Finds boundary-related errors | Finds errors in processing logic |

| Number of Tests | More test cases | Fewer test cases |

| Example (Age 18-60) | Tests: 17, 18, 19, 59, 60, 61 | Tests: 25 (one from range) |

SUMMARY TABLE: ALL TEST CASES

Problem 1: Discount Calculation

- Total Test Cases: 17

- Boundary Test Cases: 11

- Equivalence Partitioning: 6

- Invalid Cases: 3

Problem 2: Life Insurance Premium

- Total Test Cases: 20

- Boundary Test Cases: 10

- Equivalence Partitioning: 7

- Invalid Cases: 3

Problem 3: Election Voting

- Total Test Cases: 22

- Boundary Test Cases: 9

- Equivalence Partitioning: 8

- Invalid Cases: 5

Total Test Cases Designed: 59

KEY TESTING PRINCIPLES APPLIED

1. Boundary Value Analysis: Testing at exact boundaries and one step beyond

2. Equivalence Partitioning: Selecting representative values from each class

3. Negative Testing: Testing with invalid inputs

4. Edge Case Testing: Testing extreme values

5. Error Handling: Verifying system behavior with invalid data

These black box testing techniques ensure comprehensive coverage without knowledge of internal code structure.

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BLACK BOX TESTING: BOUNDARY VALUE ANALYSIS AND EQUIVALENCE PARTITIONING

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