The below three are black box design
techniques:
o Equivalence Partitioning
o Boundary Value Analysis
o Error Guessing
Equivalence Partitioning:
Equivalence partitioning is the
black box testing technique.
This technique helps us to divide
the set of test condition into a partition that can be considered the same
condition.
Advantage of this technique is to
reduce required time by testing all the required coverage of the software with
fewer test cases than many test cases.
For
Example:
Assume, text box called ‘age’ exist
in software, as per function it should accept 1 to 100 as age limit, it should
not allow to accept less than 1 and numbers greater than 100.
|
Conditions
|
Without equivalence partitioning
|
Using equivalence partitioning
|
|
Should accept 1 to 100
Should not accept negative values
(-1,0)
Should not accept (> 100)
|
It’s required to write 100
+ test cases.
Test case 1 : To test input number
‘1’,
Test case 2: To test input
number ‘2’,
Test case 3: To test input
number ‘4’…. So on up to 100
Test case 101: For >100
Test case 102: For < 1
|
It’s enough to write three
test cases to test all the condition using equivalence partitioning.
Test case 1: One valid input from
1 to 100.
Test case 2: One invalid input
< 1.
Test case 3: One invalid input
> 100.
|
Boundary Value Analysis:
Boundary value analysis is a black
box testing technique is used to test the boundary values rather than testing
the interior values.
For
Example:
Assume, text box called ‘age’ exist
in software, as per function it should accept 1 to 100 as age limit, it should
not allow to accept less than 1 and numbers greater than 100.
|
Conditions
|
Without Boundary Value Analysis
|
Using Boundary Value Analysis
|
|
Should accept 1 to 100
Should not accept negative values
(-1,0)
Should not accept (> 100)
|
It’s required to write 100
+ test cases.
Test case 1 : To test input number
‘1’,
Test case 2: To test input
number ‘2’,
Test case 3: To test input
number ‘4’…. So on up to 100
Test case 101: For >100
Test case 102: For < 1
|
It’s enough to write three
test cases to test all the condition using equivalence partitioning.
Test case 1: Input Exact boundary
value 1 and 100.
Test case 2: Below the extreme
boundary edges of input value 0 and 99.
Test case 3: Above that extreme
boundary edges of input value 2 and 101.
|
Error Guessing:
Error guessing is the black box
design technique, which focuses on identifying the defects without having
formal documentation. This technique usually performed by the experience tester
with enough knowledge on functionality.
