1. Chapter 1: Boundary Value Testing
Unit III
Chapter 1: Boundary Value Testing

2. Boundary Value Testing
Boundary value analysis is a type of black box or specification based testing technique in which tests are performed using the boundary values.
Practically, due to time and budget considerations, it is not possible to perform exhausting testing for each set of test data, especially when there is a large pool of input combinations.
We use two techniques - Equivalence Partitioning & Boundary Value Analysis testing techniques to achieve this.

3. Boundary testing is the process of testing between extreme ends or boundaries between partitions of the input values.
So these extreme ends like Start- End, Lower- Upper, Maximum-Minimum, Just Inside-Just Outside values are called boundary values and the testing is called "boundary testing".
The basic idea in boundary value testing is to select input variable values at their:
Minimum
Just above the minimum
A nominal value
Just below the maximum
Maximum

5. Example
An exam has a pass boundary at 50 percent, merit at 75 percent and distinction at 85 percent. The Valid Boundary values for this scenario will be as follows:
49, 50 - for pass
74, 75 - for merit
84, 85 - for distinction
Boundary values are validated against both the valid boundaries and invalid boundaries.
The Invalid Boundary Cases for the above example can be given as follows:
0 - for lower limit boundary value
101 - for upper limit boundary value

6. Example on Boundary Value Analysis Test Case Design Technique:
Assume, we have to test a field which accepts Age 18 – 56

7. Minimum boundary value is 18
Maximum boundary value is 56
Valid Inputs: 18,19,55,56
Invalid Inputs: 17 and 57
Test case 1: Enter the value 17 (18-1) = Invalid
Test case 2: Enter the value 18 = Valid
Test case 3: Enter the value 19 (18+1) = Valid
Test case 4: Enter the value 55 (56-1) = Valid
Test case 5: Enter the value 56 = Valid
Test case 6: Enter the value 57 (56+1) =Invalid

8. Example 2:
Assume we have to test a text field (Name) which accepts the length between 6-12 characters.

9. Minimum boundary value is 6
Maximum boundary value is 12
Valid text length is 6, 7, 11, 12
Invalid text length is 5, 13
Test case 1: Text length of 5 (min-1) = Invalid
Test case 2: Text length of exactly 6 (min) = Valid
Test case 3: Text length of 7 (min+1) = Valid
Test case 4: Text length of 11 (max-1) = Valid
Test case 5: Text length of exactly 12 (max) = Valid
Test case 6: Text length of 13 (max+1) = Invalid

10. Normal Boundary Value Testing
In the general application of Boundary Value Analysis can be done in a uniform manner. The basic form of implementation is to maintain all but one of the variables at their nominal (normal or average) values and allowing the remaining variable to take on its extreme values. The values used to test the extremities are:
Min Minimal
Min Just above Minimal
Nom Average
Max Just below Maximum
Max Maximum

12. NextDate Function
NEXTDATE is a function of three variables: month, day, and
year, for years from 1812 to It returns the date of the
next day.
NEXTDATE( Dec, 31, 1991) returns Jan
NEXTDATE( Feb, 21, 1991) returns Feb
NEXTDATE( Feb, 28, 1991) returns Mar
NEXTDATE( Feb, 28, 1992) returns Feb

13. Boundary Value Test Cases for NextDate
Month
Day
Year
Expected Output 1
1812
1, 2, 1812 2
1813
1, 2, 1813 3
1912
1, 2, 1912 4
2011
1, 2, 2011 5
2012
1, 2, 2012 6
1, 3, 1812 7
1, 3, 1813 8
1, 3, 1912 9
1, 3, 2011 10
1, 3, 2012 11 15
1, 16, 1812 12
1, 16, 1813 13
1, 16, 1912 14
1, 16, 2011
1, 16, 2012

14. Special Value Test Cases
Month
Day
Year
Reason
SV-1 2 28
2012
Feb. 28 in a leap year
SV-2
2013
Feb. 28 in a common year
SV-3 29
Leap day in a leap year
SV-4
2000
Leap day in 2000
SV-5
1900
Feb. 28 in 1900
SV-6 12 31
2011
End of year
SV-7 10
End of 31-day month
SV-8 11 30
End of 30-day month
SV-9
Last day of defined interval

15. Robustness Testing
In BVA, we remain within the legitimate boundary of our range i.e. for testing we consider values like (min, min+, nom, max-, max) whereas in Robustness testing, we try to cross these legitimate boundaries as well.
Thus for testing here we consider the values like (min-, min, min+, nom, max-, max, max+)

17. Hierarchy Boundary Value testing of n inputs : 4n + 1
Robustness testing of n inputs : 6n + 1
“Worst case” for boundary value : 5n
“Worst case” for robustness : 7n
1) Boundary Value is a subset of Robustness
2) Worst Case of boundary value is a subset of Worst Case of robustness

18. Worst case BVT

20. Test cases

22. Special Value Testing
The testing executed by Special Value Testing technique is based on past experiences, which validates that no bugs or defects are left undetected.
Moreover, the testers are extremely knowledgeable about the industry and use this information while performing Special Value testing.
Another benefit of opting Special Value Testing technique is that it is Ad-hoc in nature. There are no guidelines used by the testers other than their “best engineering judgment”.
The most important aspect of this testing is that, it has had some very valuable inputs and success in finding bugs and errors while testing a software.

23. Random Testing
Random Testing is a form of functional black box testing that is performed when there is not enough time to write and execute the tests.

24. Random Testing Characteristics
Random testing is performed where the defects are NOT identified in regular intervals.
Random input is used to test the system's reliability and performance.
Saves time and effort than actual test efforts.
Other Testing methods Cannot be used to.